Mechanically Bonded Visor System for Surgical Hood

ABSTRACT

A visor system for a surgical hood is provided. The system includes a base film and one or more removable films that are mechanical bonded (e.g., via ultrasonic energy and pressure, which allows ethylene oxide gas to penetrate between the films to provide for a “new” sterile surface should the surgeon elect to peel away a soiled or splattered removable film during the course of a surgical procedure so that an unobstructed view can be maintained. The mechanical bond points are intermittent rather than continuous so that the perimeter of the visor is not sealed, thus allowing for adequate ethylene oxide gas penetration and exposure to each of the films. Further, because the bond points are located about the perimeter of the removable films, viewing is not obscured, yet the layers are held securely in place until easily removed from the underlying removable film or base film.

RELATED APPLICATION

The present application claims priority to U.S. Provisional PatentApplication No. 62/775,988, filed on Dec. 6, 2018, the entire contentsof which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to the visor component of surgical hoodsthat can be used in conjunction with surgical gowns, helmets, andventilation systems worn by medical care providers in the operating roomor people in any other environment where exposure to hazardous materialsand liquids is a risk.

BACKGROUND OF THE INVENTION

Surgeons and other healthcare providers often wear a combination of anonwoven-based surgical suit or gown, a hood with a visor, and an aircooling or ventilation system during operating procedures, particularlyorthopedic total joint replacement surgeries such as arthroplasties andrevisions of the knee, hip, and shoulder, in order to ensure sterileconditions in the operating room, protect the wearer, and create acomfortable environment for the wearer. During the course of suchsurgeries, aerosolized or droplets of biological fluid can spray ontothe visor, obstructing the view of the surgeon or other healthcareprovider. Thus, in order to provide surgeons and other healthcareproviders with improved visibility, the visor can include one or moreremovable transparent films, where the surgeon or other healthcareprovider can remove or peel away the transparent film should it becomecovered with biological fluids, tissue, etc., thus exposing a clean,unobstructed surface of an additional removable transparent film or thetransparent base film of the visor positioned below the transparent filmthat was removed. The transparent films must be sterile, and because thetransparent films are in close contact with each other, sterilization ofthe transparent films is often problematic.

Currently, ethylene oxide (EO) gas is used to sterilize allnonwoven-based surgical suits or gowns and hoods. However, a problemexists when using EO gas to sterilize visors with multiple transparentfilms, as the transparent films are typically in direct contact witheach other, which prevents the EO gas from penetrating through theoutermost, exposed transparent film to sterilize the underlyingadditional transparent films present.

As such, a need exists for a visor design that allows for EO gas to beused to sterilize a visor having a transparent base film and one or moretransparent removable films attached thereto in conjunction with thehood and/or surgical suit or gown with which it will be worn.

SUMMARY OF THE INVENTION

In accordance with one particular embodiment of the present invention, avisor system for a personal protection system is provided. The visorsystem includes a base film and a first removable film mechanicallybonded to an outer-facing surface of the base film via a first pluralityof mechanical bond points, where gaps are present between adjacentmechanical bond points.

In another embodiment, the first removable film can include a tab, andthe tab can facilitate removal of the first removable film from the basefilm.

In still another embodiment, the base film and the first removable filmcan be transparent.

In yet another embodiment, the base film can include a polyester or apolycarbonate.

In an additional embodiment, the first removable film can include apolyester or a polycarbonate.

In one more embodiment, the first plurality of mechanical bond pointscan be ultrasonic bond points.

In another embodiment, the gaps can permit penetration of ethylene oxidegas between the base film and the first removable film.

In still another embodiment, the base film can define a perimeter andthe first removable film can define a perimeter, where the perimeter ofthe first removable film can be contained completely within theperimeter of the base film. Further, the first plurality of mechanicalbond points can be located about the perimeter of the first removablefilm.

In yet another embodiment, the visor system can further include a secondremovable film, where the second removable film can be mechanicallybonded to the first removable film via a second plurality of mechanicalbond points, where gaps can be present between adjacent mechanical bondpoints.

In an additional embodiment, the second removable film can include atab, where the tab can facilitate removal of the second removable filmfrom the first removable film.

In one more embodiment, the second removable film can be transparent.

In another embodiment, the second removable film can include a polyesteror a polycarbonate.

In still another embodiment, the second plurality of mechanical bondpoints can be ultrasonic bond points.

In yet another embodiment, the gaps can permit penetration of ethyleneoxide gas between the first removable film and the second removablefilm.

In an additional embodiment, the base film can define a perimeter andthe second removable film can define a perimeter, where the perimeter ofthe second removable film can be contained completely within theperimeter of the base film. Further, the second plurality of mechanicalbond points can be located about the perimeter of the second removablefilm.

In one more embodiment, the visor system can be ethylene oxide gassterilized.

In accordance with another particular embodiment of the presentinvention, a surgical hood comprising the visor system as describedabove is provided, where the surgical hood and the visor system areethylene oxide gas sterilized.

In accordance one more embodiment of the present invention, surgicalgown comprising an integrated surgical hood and the visor system asdescribed above is provided, where the surgical gown, the integratedsurgical hood, and the visor system are ethylene oxide gas sterilized.

A personal protection system including a surgical gown and a separatesurgical hood comprising the visor system as described above is alsocontemplated by the present invention, where the personal protectionsystem is ethylene gas sterilized in a single package.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE FIGURES

A full and enabling disclosure of the present invention to one skilledin the art, including the best mode thereof, is set forth moreparticularly in the remainder of the specification, including referenceto the accompanying figures, in which:

FIG. 1 illustrates a front view of a visor system according to oneembodiment of the present invention;

FIG. 2 illustrates a front view of another visor system according to oneembodiment of the present invention;

FIG. 3A illustrates a cross-sectional view of one of the removable filmsof the visor system of the present invention;

FIG. 3B illustrates a perspective view of the removable film of FIG. 3A;

FIG. 4A illustrates a cross-sectional view of the visor system of thepresent invention where one removable film is mechanically bonded to abase film;

FIG. 4B illustrates a perspective view of the visor system of FIG. 4A;

FIG. 5A illustrates a cross-sectional view of the visor system of thepresent invention where a first removable film is mechanically bonded toa base film and a second removable film is mechanically bonded to thefirst removable film;

FIG. 5B illustrates a perspective view of the visor system of FIG. 5A;

FIG. 6 illustrates a side view of a user wearing a personal protectionand ventilation system, including a disposable surgical gown, a hoodwith which the visor system of the present invention is integrated, anda helmet;

FIG. 7 illustrates a procedure for donning the disposable surgical gownand hood with which the visor system of the present invention isintegrated;

FIG. 8 illustrates various adjustment procedures that can be carried outwhile using a personal protection and ventilation system that includesthe visor system of the present invention.

FIG. 9 illustrates a personal protection and ventilation system withwhich the visor system of the present invention can be used;

FIG. 10 illustrates a front view of one embodiment of a disposablesurgical gown with which the visor system of the present invention canbe used;

FIG. 11 illustrates a rear view of one embodiment of the disposablesurgical of FIG. 10;

FIG. 12 illustrates a front view of another embodiment of a disposablesurgical gown with which the visor system of the present invention canbe used;

FIG. 13 illustrates a rear view of the disposable surgical gown of FIG.12;

FIG. 14 illustrates a cross-sectional view of one embodiment of a firstmaterial used in forming the front panel, sleeves, and hood of adisposable surgical gown with which the visor system of the presentinvention can be used; and

FIG. 15 illustrates a cross-sectional view of one embodiment of a secondmaterial used in forming the first rear panel and the second rear panelof a disposable surgical gown with which the visor system of the presentinvention can be used.

FIG. 16 illustrates a front view of a visor system according to oneembodiment of the present invention.

FIG. 17 illustrates a front view of a visor system according to anotherembodiment of the present invention.

FIG. 18 illustrates a front view of a visor system according to stillanother embodiment of the present invention.

FIG. 19 illustrates a perspective view of a visor system according toone embodiment of the present invention, where one layer of removablefilm is being removed from a base film.

FIG. 20 illustrates a zoomed in view of a visor system according to oneembodiment of the present invention showing one of the ultrasonicwelding sections in detail.

FIG. 21 illustrates a zoomed in view of a visor system according toanother embodiment of the present invention showing one of theultrasonic welding sections in detail.

FIG. 22 illustrates a zoomed in view of a visor system according to yetanother embodiment of the present invention showing one of theultrasonic welding sections in detail.

Repeat use of reference characters in the present specification anddrawings is intended to represent the same or analogous features orelements of the present invention.

Definitions

As used herein, the term “spunbond” refers to fabric made from smalldiameter fibers which are formed by extruding molten thermoplasticmaterial as filaments from a plurality of fine, usually circularcapillaries of a spinneret with the diameter of the extruded filamentsthen being rapidly reduced as by, for example, in U.S. Pat. No.4,340,563 to Appel et al., and U.S. Pat. No. 3,692,618 to Dorschner etat, U.S. Pat. No. 3,802,817 to Matsuki et al., U.S. Pat. Nos. 3,338,992and 3,341,394 to Kinney, U.S. Pat. No. 3,502,763 to Hartman, and U.S.Pat. No. 3,542,615 to Dobo et al. Spunbond fibers are generally nottacky when they are deposited onto a collecting surface. Spunbond fibersare generally continuous and have average diameters (from a sample of atleast 10) larger than 7 microns, more particularly, between about 10 and20 microns.

As used herein, the term “meltblown” refers to fabric formed byextruding a molten thermoplastic material through a plurality of fine,usually circular, die capillaries as molten threads or filaments intoconverging high velocity, usually hot, gas (e.g. air) streams whichattenuate the filaments of molten thermoplastic material to reduce theirdiameter, which may be to microfiber diameter. The meltblown fibers arethen carried by the high velocity gas stream and are deposited on acollecting surface to form a web of randomly dispersed meltblown fibers.Such a process is disclosed, for example, in U.S. Pat. No. 3,849,241 toButin et al. Meltblown fibers are microfibers which may be continuous ordiscontinuous, are generally smaller than 10 microns in averagediameter, and are generally tacky when deposited onto a collectingsurface.

As used herein, the term “SMS laminate” refers to fabric laminates ofspunbond and meltblown fabrics, e.g., spunbond/meltblown/spunbondlaminates as disclosed in U.S. Pat. No. 4,041,203 to Brock et al., U.S.Pat. No. 5,169,706 to Collier, et al, U.S. Pat. No. 5,145,727 to Pottset al., U.S. Pat. No. 5,178,931 to Perkins et al. and U.S. Pat. No.5,188,885 to Timmons et al. Such a laminate may be made by sequentiallydepositing onto a moving forming belt first a spunbond fabric layer,then a meltblown fabric layer and last another spunbond layer and thenbonding the laminate in a manner described below. Alternatively, thefabric layers may be made individually, collected in rolls, and combinedin a separate bonding step. Such fabrics usually have a basis weight offrom about 0.1 osy to 12 osy (about 3.4 gsm to about 406 gsm), or moreparticularly from about 0.75 to about 3 osy (about 25.4 gsm to about101.7 gsm).

DETAILED DESCRIPTION OF REPRESENTATIVE EMBODIMENTS

Reference now will be made in detail to various embodiments of theinvention, one or more examples of which are set forth below. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations may be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment, may be used on another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

Generally speaking, the present invention is directed to a visor systemfor a surgical hood that can be a component of a personal protectionsystem, which can include a ventilation system in some embodiments. Thevisor system includes a transparent base film and one or more removabletransparent films attached to an outer-facing surface of the transparentbase film. The one or more removable transparent films can be attachedto the transparent base film and/or each other by mechanical bonding. Inone particular embodiment, the type of mechanical bonding can beultrasonic bonding. Specifically, a first removable transparent film canbe attached to the base transparent film by mechanical bonding, and asecond removable transparent film can be attached to the first removabletransparent film by mechanical bonding.

Further, to ensure that each of the transparent films and the base filmare able to be adequately sterilized by ethylene oxide (EO) gas, thetransparent films are attached to each other via mechanical bond points(e.g., bond points formed via ultrasonic bonding) intermittently spacedaround the perimeter of the removable transparent films. As such, aplurality of gaps can separate adjacent mechanical bond points to permitEO gas to penetrate each of the films to sterilize all surfaces of thefilms. Such an arrangement allows each underlying film of the visorsystem that is exposed after peeling away an outermost film anddiscarding the outermost film to be adequately sterilized by EO gas.Further, it is to be understood that because the transparent films ofthe present invention can be formed from polycarbonate or polyester,which are materials through which EO gas cannot penetrate, the pluralityof gaps between the mechanical bond points required by the presentinvention are important to ensuring adequate sterilization by EO gas. Incontrast, the use of an adhesive around the entire perimeter of theremovable transparent films to attach the removable transparent films tothe base film and/or each other would not allow for EO gas penetration.

In other words, utilizing the mechanical bonding approach contemplatedby the visor system of the present invention allows sterilizing EO gasto penetrate between the transparent films, which is in stark contrastto current film attachment methods that utilize adhesives. Becauseethylene oxide gas cannot penetrate films bonded together via adhesivesand cannot penetrate polyester and polycarbonate transparent films,unlike the visor system of the present invention, currently availablevisor systems often require the use of radiation sterilization (e.g.,gamma radiation) as an interim step to sterilize the visor systemseparately before the visor system can be incorporated into a surgicalhood, which is then sterilized by, for instance, EO gas, resulting in avery inefficient and time-consuming sterilization process.

On the other hand, the intermittently spaced mechanical bond pointscontemplated by the present invention allow sufficient ethylene oxidegas exposure to kill biological indicator (BI) microbes to yield anunderlying sterile surface. The resulting multi-layer visor system ofthe present invention can thus be formed and then bonded or otherwiseattached to a surgical hood or a surgical gown with attached hood, andthe entire protective surgical garment can then be sterilized in onestep via exposure to ethylene oxide gas, rather than having to sterilizethe individual components in multiple steps as required for currentlyavailable multi-layer visor systems. This is because the gaps betweenthe intermittent bond points allow the EO gas to penetrate the multiplefilms of the visor system during sterilization. This results in asurgical hood and/or gown where all of the transparent films (e.g., thebase film and one or more removable films) are sterile in the event thatone or more of the outermost transparent films are peeled away from thevisor system and discarded as they become soiled.

In addition, it is to be understood that the visor system of the presentinvention contemplates placement of the intermittently spaced mechanicalbond points around the perimeter of the removable transparent films ofthe visor system so as to be unobtrusive to the surgeon or otherhealthcare provider. Moreover, the various transparent films areattached to each other with a bond strength sufficient to secure thetransparent films to each other when in use, while also allowing for thesurgeon or other healthcare provider to easily peel away and remove anoutermost soiled transparent film without dislodging the other layersand the underlying helmet to which the surgical hood and visor system issecured.

As mentioned above, to create the mechanical bond points that areintermittently spaced about the perimeter of the visor system of thepresent invention, mechanical bonding in the form of ultrasonic bondingcan be used. Ultrasonic bonding utilizes ultrasonic energy, pressure,weld time, and hold time parameters to melt polymeric films (e.g.,polyester or polycarbonate transparent films). For instance, themechanical bond points can be formed using an ultrasonic plunge weldersuch as a Branson ultrasonic plunge welder utilizing a power supplyhaving a wattage of at least 2200 Watts, such as from about 2200 Wattsto about 4000 Watts, such as from about 2600 Watts to about 3400 Watts.The weld time can range from about 0.04 seconds to about 0.12 seconds,such as from about 0.05 seconds to about 0.10 seconds, such as fromabout 0.06 seconds to about 0.08 seconds. Further, the hold time afterwelding can range from about 0.1 second to about 1 second, such as fromabout 0.2 seconds to about 0.8 seconds, such as from about 0.4 secondsto about 0.6 seconds. In addition, the pressure applied during weldingcan range from about 10 pounds per square inch (psi) to about 40 psi,such as from about 15 psi to about 35 psi, such as from about 20 psi toabout 30 psi.

Regardless of the specific welding parameters utilized, the resultingmechanical (e.g., ultrasonically welded) bond points are intermittentlyspaced apart from each other about the perimeter of the removabletransparent films in the visor system of the present invention so thereis no continuous seal around the perimeter of the removable transparentfilms. Thus, the specific bond pattern contemplated by the presentinvention allows for EO gas penetration at the gaps located between eachof the mechanical bond points and allows the gas to contact each of thefilms' surfaces to ensure adequate sterilization. Further, by locatingthe mechanical bond points on the outer perimeter of the transparentfilms of the visor system, viewing is not obscured, yet the transparentfilms are held securely in place until the transparent films need to bepeeled away from visor system. The various features of the visor system180 of the present invention are discussed in more detail withreferences to FIGS. 1-8.

Turning first to FIG. 1, a front view of one visor system 180contemplated by the present invention is shown. The visor system 180includes a base film 112 having a perimeter P1 and also having anouter-facing surface 270 that is exposed to the environment whenincorporated into a surgical hood and an inner-facing surface 272 (seeFIGS. 4A-5B) that is the surface closest to a wearer's face whenincorporated into a surgical hood. The base film 112 can include tabs A1and A2 extending from a first side 266 and a second side 268 of thevisor system 180. Tabs A1 and A2 can be used to secure the visor system180 to a surgical hood, such as surgical hood 178 shown in FIGS. 6-8.The visor system 180 also includes at least one removable film 114having a perimeter P2 that can be contained completely within theperimeter P1 of the base film layer 112. In some embodiments, the visorsystem 180 can include one or more additional removable films, such asremovable film 116. The removable films 114 and 116 can each includetabs (e.g., tabs B and C) that enable the wearer to peel-away theoutermost removable film 114 or 116 when it becomes soiled or when thewearer's visibility is otherwise diminished due to the presence ofblood, tissue, or other matter coming into contact with the film 114 or116. As shown in FIG. 1, in some embodiments, the tabs B and C can bothbe present on the first side 266 of the visor system 180. Meanwhile,referring to FIG. 2, in other embodiments, the tabs B and C can be onopposing sides of the visor system 180. For instance, tab B, which isassociated with the removable film 114, can be present on the first side266 of the visor system 180, while tab C, which is associated with theremovable film 116, can be present on the second side 268 of the visorsystem 180.

The base film 112 can have a height H1 in the y-direction ranging fromabout 15 centimeters (cm) to about 35 cm, such as from about 17.5 cm toabout 30 cm, such as from about 20 cm to about 25 cm.

Meanwhile, the removable films 114 and 116 can have a height H2 in they-direction ranging from about 10 cm to about 30 cm, such as from about12.5 cm to about 25 cm, such as from about 15 cm to about 20 cm.

Further, the each of the tabs A1, A2, B, and C can have a height H3 inthe y-direction ranging from about 0.5 cm to about 3 cm, such as fromabout 0.75 cm to about 2.5 cm, such as from about 1 cm to about 2 cm.

In addition, the base film 112 can have an overall width W1 in thex-direction including the width of the tabs A1 and A2 ranging from about35 cm to about 50 cm, such as from about 37.5 cm to about 47.5 cm, suchas from about 40 cm to about 45 cm, and a width W2 in the x-directionexcluding the width of the tabs A1 and A2 ranging from about 32.5 cm toabout 47.5 cm, such as from about 35 cm to about 45 cm, such as fromabout 37.5 cm to about 42.5 cm.

Moreover, the removable films 114 and 116 can have a width W3 in thex-direction excluding the width of the tabs B and C ranging from about25 cm to about 42.5 cm, such as from about 27.5 cm to about 40 cm, suchas from about 30 cm to about 37.5 cm.

Additionally, the tabs A1, A2, B, and C can have a width W4 ranging fromabout 0.5 cm to about 3 cm, such as from about 0.75 cm to about 2.75 cm,such as from about 1 cm to about 2 cm.

Further, regardless of the dimensions of each of the films 112, 114, and116, or the number of removable films present in the visor system 180,the films can each be transparent and can each be formed frompolycarbonate or polyester. In one particular embodiment, the films 112,114, and 116 can be polyester. Further, the base film 112 can have athickness in the z-direction ranging from about 150 micrometers to about350 micrometers, such as from about 175 micrometers to about 325micrometers, such as from about 200 micrometers to about 300micrometers, while the removable films 114 and 116 can each have athickness in the z-direction ranging from about 10 micrometers to about125 micrometers, such as from about 25 micrometers to about 100micrometers, such as from about 50 micrometers to about 75 micrometers.

Turning now to FIGS. 3A to 5B, the attachment of the base film 112 tothe one or more removable films 114 and 116 via mechanical bonding(e.g., ultrasonic bonding) is shown in detail. FIG. 3A illustrates across-sectional view of one of the removable films 114 or 116 of thevisor system 180 of the present invention, while FIG. 3B illustrates aperspective view of the removable film 114 or 116 of FIG. 3A. FIG. 4Aillustrates a cross-sectional view of the visor system 180 of thepresent invention where one removable film 114 or 116 is mechanicallybonded to the base film 112, while FIG. 4B illustrates a perspectiveview of the visor system 180 of FIG. 4A. FIG. 5A illustrates across-sectional view of the visor system 180 of the present inventionwhere a first removable film 114 is mechanically bonded to the base film112 and a second removable film 116 is mechanically bonded to the firstremovable film 114, while FIG. 5B illustrates a perspective view of thevisor system of FIG. 5A.

As shown in FIGS. 3A and 3B, the removable films 114 and 116 can eachinclude a biological indicator 128 attached, for example, to a centrallylocated surface of the removable film 114 or 116, such as via one ormore strips of tape 132 or any other suitable attachment means. Thebiological indicator 128 can be used to ensure that the removable films114 and 116 are adequately sterilized via EO gas in a single,simultaneous, efficient, sterilization step when sterilized separatelyor as part of a single package that includes a surgical gown 101 and/orsurgical hood 178 of a personal protection and ventilation system 100.

Next, as shown in FIGS. 4A and 4B, once the biological indicator 128 isattached to the removable film 114 or 116, the removable film 114 or 116can be mechanically bonded to an outer-facing surface 270 of a base film112, while the inner-facing surface 272 of the base film 112 is thesurface closest to a wearer's face when incorporated into a surgicalhood 178 as described in more detail below. For the purposes of FIGS. 4Aand 4B, reference is made to removable film 114. As shown, a pluralityof mechanical bond points 124 can be disposed about a perimeter P2 ofthe removable film 114 between the removable film 114 and theouter-facing surface 270 of the base film 112 to join the two filmstogether, while at the same time, a gap 126 is present between adjacentmechanical bond points 124 to ensure that all of the surfaces of thebase film 112 and removable film 114 can be adequately sterilized. Themechanical bond points 124 can be formed via any suitable means, such asultrasonic welding.

Further, as shown in FIGS. 5A and 5B, once the removable film 114 ismechanically bonded to the base film 112 as described above withreference to FIGS. 4A and 4B, an additional removable film 116 can bemechanically bonded to the removable film 114. Again, similar to themechanical bonding between the base film 112 and the removable film 114,a plurality of mechanical bond points 124 can be disposed about aperimeter P2 of the removable films 114 and 116 between the removablefilm 116 and the removable film 114 to join the two films together,while at the same time, a gap 126 is present between adjacent mechanicalbond points 124 to ensure that all of the surfaces of removable film 114and the removable film 116 can be adequately sterilized. The mechanicalbond points 124 can be formed via any suitable means, such as ultrasonicwelding.

Turning now to FIGS. 16-22, specific examples of the arrangement of theplurality of mechanical bond points 124 are described in more detail,although it is to be understood that the configuration of the variouspatterns and spacing of the mechanical bond points 124 can vary based onapplication and the type of sterilization cycle utilized to sterilizethe visor system 180. It is also to be understood that the plurality ofmechanical bond points 124 distributed or disposed about a perimeter P2of the removable films 114 and/or 116 can be made using, for example, amale knurled patterned horn interfacing with a flat surface. The maleknurled pattern horn can come in a variety of shapes and dimensions toform a plurality of mechanical bond points 124 having a variety ofshapes (e.g., circular, arcuate, rectangular, square, triangular,elliptical, hexagonal, etc.). Further, by controlling the depth of thebond formed by the patterned horn, more than one peelable or removablefilm can be adhered to another layer simultaneously. For instance, afirst removable film 114 can be adhered to a base film 112, and a secondremovable film 116 can be adhered to the first removable film 114.Further, each the plurality of mechanical bond points 124 formed betweenthe second removable film 116 and the first removable film 114 can beadjacent to or concentrically positioned around the plurality ofmechanical bond points 124 formed between the base film 112 and thefirst removable film 114 in the same knurled pattern. In addition, it isto be understood that although anvils are not required to form thepatterns of the mechanical bond points 124 since the horn may bepatterned with the male knurl pattern, a multi-plunge process could alsobe used where multiple anvils are mounted to a single receiving platethat receives multiple horns executing multiple plunges at one time.

The various parameters that can be controlled during bonding to form thedesired mechanical bond points via ultrasonic bonding are shown below inTable 1:

TABLE 1 Ultrasonic Bonding Parameters Parameter Range Frequency 20 kHzPower Supply 4000 Watts Weld Time 0.010 seconds-0.300 seconds Collapse0.001″-0.0075″ (0.00254 cm-0.01905 cm) Energy 0.5 Joules-1.5 Joules HoldTime 0.01 seconds-0.5 seconds Trigger Pressure 1 pound-10 pounds (0.45kg-4.5 kg) Gauge Pressure 10 psi-50 psi (0.069 MPa-0.35 MPa) Down Speed1 inch/sec-1.75 inch/second (2.54 cm/sec-4.45 cm/sec) Amplitude 25%-85%Peak Power 10%

Now, various examples of patterns of mechanical bond points 124 will bediscussed in more detail. Specifically, FIG. 16 illustrates a front viewof a visor system 180 according to one embodiment of the presentinvention. In FIG. 16, the plurality of mechanical bond points 124 arearranged about the perimeter P2 of the removable film 114 in the form ofcircles having a diameter D. The diameter D can be any suitable diameterbut, in some embodiments, can range from about 0.5 centimeters to about2 centimeters, such as from about 0.75 centimeters to about 1.75centimeters, such as from about 1 centimeter to about 1.5 centimeters.Moreover, if an additional removable film 116 (not shown) is included inthe visor system 180, it can be attached to the first removable film 114via a plurality of bond points 124 that can be in the form of a circleor any other suitable geometry can be positioned adjacent orconcentrically around the outer edge of the plurality of bond points 124joining the first removable film 114 to the base film 112. The firstremovable film 114 also includes tabs B1 and B2 to facilitate peeling ofthe first removable film 114 from the base film 112.

Further, FIG. 17 illustrates a front view of a visor system 180according to another embodiment of the present invention. As shown,plurality of mechanical bond points 124 are in the form of an arcuateshape at the corners of the first removable film 114, where the arcuateshape follows the radius of curvature of the removable film layer 114,which includes tabs B1 and B2. The arcuate shape can have an arc lengthL2 ranging from about 10 centimeters to about 15 centimeters, such asfrom about 11 centimeters to about 14 centimeters, such as from about 12centimeters to about 13 centimeters, while the radius of curvature R canrange from about 3.5 centimeters to about 5.5 centimeters, such as fromabout 3.75 centimeters to about 5.25 centimeters, such as from about 4centimeters to about 5 centimeters. In addition, each of the arcuatemechanical bond points 124 can terminate in a straight lineperpendicular to the edge of the removable film layer 114. Further, themechanical bond points 124 can have a height H4 ranging from about 0.4centimeter to about 0.9 centimeters, such as from about 0.5 centimetersto about 0.8 centimeters, such as from about 0.6 centimeters to about0.7 centimeters. Without intending to be limited by any particulartheory, the present inventors have found that such features anddimensions allow for a more continuous peel of the first removable film114 from the base film 112 when in use. Additionally, a series of dashesor reference lines can be permanently or temporarily disposed on thefirst removable film 114, the base film 112, or both to ensure that thearcuate-shaped mechanical bond points 124 positioned at the corners ofthe first removable film 114 are aligned with each other.

Meanwhile, FIG. 18 illustrates a front view of a visor system 180according to still another embodiment of the present invention where oneof the plurality of mechanical bond points 124 at an upper edge of theremovable film layer 114 can be in the shape of a rectangle that canhave a height H4 ranging from about 0.4 centimeter to about 0.9centimeters, such as from about 0.5 centimeters to about 0.8centimeters, such as from about 0.6 centimeters to about 0.7 centimetersand a length ranging from about 2 centimeters to about 8 centimeters,such as from about 3 centimeters to about 7 centimeters, such as fromabout 4 centimeters to about 6 centimeters, where the features anddimensions allow for a more continuous peel of the first removable film114 from the base film 112 when in use.

In addition, FIGS. 19-22 illustrate various zoomed in views ofadditional visor systems 180 of the present. For instance, FIG. 19 showsthe peeling of a removable film 114 from a base film 112, where amechanical bond point 124 is shown as being positioned on both theremovable film 114 and the base film 112. Further, FIG. 20 illustrates azoomed in view of the rectangular shaped mechanical bond point 124 ofthe visor system 180 of FIG. 18. Moreover, FIG. 21 illustrates a zoomedin view of one of the arcuate-shaped mechanical bond points 124 of thevisor system 180 of FIGS. 17-18. Lastly, FIG. 22 illustrates a zoomed inview of a visor system 180 according to yet another embodiment of thepresent invention showing one of the circular-shaped mechanical bondpoints 124 of FIG. 16 in more detail.

FIGS. 6-8 demonstrate the use of the visor system 180 of the presentinvention that includes the base film 112 and one or more removablefilms 114 and 116 described above in conjunction with a personalprotection and ventilation system 100. FIG. 6 illustrates a side view ofa user wearing a personal protection and ventilation system 100 thatincludes the visor system 180 of the present invention once completelydonned. The user or wearer's head is completely contained within a hood178, while the visor system 180 of the present invention providesvisibility in the form of a clear shield, and a light source 188 on ahelmet 190 provides illumination during a surgical procedure. Further,the hood 178 is connected to the helmet 190 via connecting tabs 210 (seeFIG. 7) present on the first side 266 and the second side 268 of thevisor system 180, where the connecting tabs 210 mate or lock with thereceiving tabs 208 on either side of the helmet 190.

Referring now to FIGS. 7-8, FIG. 7 illustrates a procedure for donningthe disposable surgical gown 101 and hood 178 with which the visorsystem 180 of the present invention is integrated, while FIG. 8illustrates various adjustment procedures that can be carried out whileusing a personal protection and ventilation system 100 that includes thevisor system 180 of the present invention. First, in FIG. 7, a procedureby which a wearer can don the disposable surgical gown 101 with hood 178and visor system 180 after donning the helmet 190, an air tube 184, anda fan component or module 186 of the personal ventilation and protectionsystem 100 as described in more detail below with respect to FIG. 9 isshown. First, with an assistant, the wearer can insert his arms into thesleeves of the disposable surgical gown 101. Then, in step 2, theassistant can bend the connecting tabs 210 on the visor system 180towards each other in the direction of the arrows as shown, and, next,in step 3, the assistant can move the hood 178 in the direction of thewearer to line up the connecting tabs 210 on the visor system 180 on thehood 178 with the receiving tabs 210 on the helmet 190. Further, as thevisor system 180 is connected to the helmet 190, in step 4, theassistant can position the hood 178 over the helmet 190 and the air tube184. Then, in step 5, the assistant can ensure that the hood 178 andgown 101 are properly donned and positioned about the body of thewearer, and lastly, in step 6, the assistant can secure the gown 101 viafastening means 118 (e.g., a zipper) by pulling the zipper downward asshown.

Further, in FIG. 8, various adjustment procedures that can be carriedout while using the personal protection and ventilation system 100including the visor system 180 of the present invention are shown. Inframes A and B, the removal of an outermost transparent or clear film114 or 116 disposed on the visor system 180 of the hood 178 is shown,leaving base film 112 exposed. Removal of the film 114 or 116 may bedesired when blood, tissue, etc. are present on the outermost film(e.g., removable film 114 or 116) and affect the wearer's visibilityduring a surgical procedure. In frame C, adjustment of the positioningof the light source 188 is shown by the wearer grasping the lever 194,where the hood 178 is present between the wearer's fingers and the lever194 contained within the hood 178. Lastly, in frame D, adjustment of thespeed of the fan 182 by an assistant is shown, where the fan 182 can beadjust to three different speeds (e.g., low, medium, and high) byturning a fan speed adjustment knob 264 either by unfastening (e.g.,unzipping) the gown 101 via fastening means 118 (see FIG. 7, step 6), ortactically through the gown 101 without unfastening the gown 101.

The various components of a personal protection and ventilation system100 with which the visor system 180 of the present invention can be usedare discussed in more detail with references to FIGS. 9-15.

FIG. 9 illustrates the various components of a personal protection andventilation system 100 that can include the visor system 180 of thepresent invention. The system 100 can include a disposable surgical gown101 that can include a separate or integral hood 178 and visor system180; and a helmet 190 that can include a front portion 252 withreceiving tabs 208 for connecting with the hood 178 via connecting tabs210 present on the visor system 180 (see FIG. 7), an air conduit 228with an air outlet 214, and a light source 188 with a support 196. Asshown in FIG. 9, the air outlet 214 can be positioned at an angle α thatranges from about 40° to about 85°, such as from about 45° to about87.5°, such as from about 50° to about 80° with respect to a y-axis orhorizontal direction towards an x-axis or vertical direction. It isbelieved that angles falling within the aforementioned ranges allow fora direction of air flow that reduces fogging in the visor system 180,limits drying of the wearer's eyes, and also provides sufficient coolingto the light source 188.

Referring still to FIG. 9, the system 100 can also include an air tube184 as well as a fan component or module 186 that includes a fan 182 andcan also include a built-in power source 216 such as a battery, a powerswitch 262, and a fan speed adjustment knob 264. However, it is also tobe understood that the power source 216 can be a separate component fromthe fan component or module 186 that is attached separately to the belt206. Further, the air tube 184 can be attached to the fan component ormodule 186 via fitting 224, while the air tube 184 can be attached tothe helmet 190 via fitting 226 at an opposite end of the air tube 184.The fan component or module 186 can be attached to a belt 206 to securethe fan component or module 186 about the rear waist area of a wearer,and the fan component or module 186 can be attached to the belt 206 viaattachment or locking mechanism 198.

FIG. 10 illustrates a front of the disposable surgical gown 101 of FIG.9 that can be used in conjunction with the visor system 180 of thepresent invention. The disposable surgical gown includes a front 158 anda rear 160 that can be worn by medical personnel during a surgicalprocedure, such as an orthopedic surgical procedure or any otherprocedure where protection from bodily fluids, bone fragments, etc. isdesired. The disposable surgical gown 101 has a waist portion 130defined between a proximal end 154 and a distal end 156, where theproximal end 154 and the distal end 156 define a front panel 102. Asshown, the proximal end 154 includes a hood 178 with the visor system180, while the distal end 156 defines a portion of the gown 101 that isclosest to the wearer's feet. As shown in FIG. 10, the hood 178 can beintegral with the gown 101 such that the gown 101 and hood 178 form asingle garment, where the hood 178 can be sewn to the gown 101 at seam170. On the other hand, as shown in FIG. 12, in some embodiments, thehood 178 can be a separate component from the surgical gown 101, wherethe hood 178 can be tucked into the surgical gown 101 inside collar 110.The gown 101 also includes sleeves 104 and cuffs 106. The front panel102, sleeves 104, and hood 178 can be formed from a laminate of anelastic film and nonwoven materials, as discussed in more detail below.Further, the sleeves 104 can be raglan sleeves, which means that eachsleeve 104 extends fully to the collar 110 (see FIG. 12), where a frontdiagonal seam 164 extends from the underarm up to the collarbone of thewearer and a rear diagonal seam 166 (see FIG. 11) extends from theunderarm up to the collarbone of the wearer to attach the sleeves 104 tothe front panel 102 and rear panels 120 and 122 of the gown 101. Thefront diagonal seams 164 and the rear diagonal seams 166 of the sleeves104 can be sewn to the front panel 102 and rear panels 120 and 122 ofthe gown. Further, the each sleeve 104 can include a seam 176 that canextend from the underarm area down to the cuff 104, where such sleeves176 can be seamed thermally so that the sleeves 104 pass ASTM-1671“Standard Test Method for Resistance of Materials Used in ProtectiveClothing to Penetration by Blood-Borne Pathogens Using Phi-X174Bacteriophage Penetration as a Test System.”

FIG. 11 illustrates a rear of the disposable surgical gown 101. Theproximal end 154 and the distal end 156 define a first rear panel 120and a second rear panel 122. The first rear panel 120 and second rearpanel 122 can be formed of a laminate of nonwoven materials, asdiscussed in more detail below. Further, as shown in FIG. 11, the hood178 can be integral with the gown 101 such that the gown 101 and hood178 form a single garment, where the hood 178 can be sewn to the gown101 at seam 170. On the other hand, as shown in FIG. 13, in someembodiments, the hood 178 can be a separate component from the surgicalgown 101, where the hood 178 can be tucked into the surgical gown 101inside collar 110. In addition, as shown in FIGS. 11 and 13, the hood178 can include a first portion 256 and a second portion 256 asseparated by a seam 254, where such the materials used to form the firstand second portions 258 materials will be discussed in more detailbelow, although, in some embodiments, it is to be understood that thehood 178 can be formed entirely of a first material 256. Further, thefirst rear panel 120 can be sewn to the front panel 102 at a seam 172,while the second rear panel 122 can be sewn to the front panel 102 at aseam 174, where the first rear panel 120 can be ultrasonically bonded tothe front panel 102 at seam 172 and the second rear panel 122 can beultrasonically bonded to the front panel 102 at seam 174, where theultrasonic bonding results in seams 172 and 174 that have improvedliquid barrier protection than sewn seams. For instance, such ultrasonicbonding of the rear panels 120 and 122 to the front panel 102 can resultin seams 172 and 174 that can have a hydrohead ranging from about 25 cmto about 100 cm, such as from about 30 cm to about 75 cm, such as fromabout 40 cm to about 60 cm, while sewn seams only have a hydrohead ofabout 7 cm, where the hydrohead is determined by providing a clearopen-ended tube and clamping the seamed material over the bottom end,filling the tube slowly with water from its top end, and measuring howhigh the column of water is before water passes through the bottom endof the tube. Further, a rear fastening means 118 such as zipper can beused to secure the gown 101 once it is worn by the wearer. Depending onwhether the hood 178 is integral with the gown 101 or separate from thegown 101, the fastening means 118 can extend into the area of the hood178 (see FIG. 11) or can end at the collar 110 (see FIG. 13).

FIG. 14 illustrates a cross-sectional view of a first material 200 whichcan be used to form the front panel 102, the sleeves 104, and the hood178 of the surgical gown 101 of FIGS. 9-13, where the first material 200passes ASTM-1671 “Standard Test Method for Resistance of Materials Usedin Protective Clothing to Penetration by Blood-Borne Pathogens UsingPhi-X174 Bacteriophage Penetration as a Test System.” In someembodiments, the entire hood 178 can be formed from the first material200, while, in other embodiments, as shown in FIGS. 10-13, the firstportion 256 of the hood 178, which encompasses the entire hood 178 atthe front 158 of the gown 101 and the portion of the hood 178 above seam254 on the rear of the gown 160 and can be formed from the firstmaterial 200, while the second portion 258 of the hood can be formedfrom a second material 300 as discussed in more detail below. The firstmaterial 200 can be a laminate that includes an outer spunbond layer142, an elastic film 144 containing an first skin layer 144A and asecond skin layer 144C with a core layer 144B disposed therebetween, anda spunbond-meltblown-spunbond laminate 146 containing a spunbond layer146A and a spunbond layer 146C with a meltblown layer 146B disposedtherebetween. The outer spunbond layer 142 can form an outer-facingsurface 202 of the front panel 102 on the front 158 of the gown 101, thesleeves 104, and the hood 178, while the spunbond layer 146C of the SMSlaminate 146 can form the body-facing surface or inner-facing surface204 of the front panel 102 and the sleeves 104 of the surgical gown 101as well as the hood 178. As discussed in more detail below, the outerspunbond layer 142 and one or more layers of the SMS laminate 146 caninclude a slip additive to enhance the softness and comfort of the firstmaterial 200, while one or more layers of the elastic film 144 caninclude a fluorochemical additive to enhance the barrier performance ofthe first material 200. The overall spunbond-film-SMS laminatearrangement of the first material 200 contributes to the moisture vaporbreathability of the surgical gown 101 while providing impermeability toair to protect the wearer from exposure to blood, viruses, bacteria, andother harmful contaminants. In other words, the first material 200allows for an air volumetric flow rate ranging that is less than about 1standard cubic feet per minute (scfm), such as less than about 0.5 scfm,such as less than about 0.25 scfm, such as less than about 0.1 scfm,such as 0 scfm, as determined at 1 atm (14.7 psi) and 20° C. (68° F.).

FIG. 15 illustrates a second material 300 that can be used to form thesurgical gown 101 of FIGS. 9-13, where the second material 300 can formthe first rear panel 120 and the second rear panel 122. Further, in someembodiments as shown in FIGS. 11 and 13, the second portion 258 of thehood 178 below seam 254 on the rear of the gown 160 can be formed fromthe second material 300 to provide some breathability to the second orlower portion 258 of the hood 178. The second material 300 can be alaminate that includes a first spunbond layer 148, a meltblown layer150, and a second spunbond layer 152. The first spunbond layer 148 canform an outer-facing surface 302 of the first rear panel 120 and thesecond rear panel 122 of the surgical gown 101, while the secondspunbond layer 152 can form the body-facing surface or inner-facingsurface 304 of the first rear panel 120 and the second rear panel 122 ofthe surgical gown 101. As discussed in more detail below, the spunbondlayers 148 and 152 can include a slip additive to enhance the softnessand comfort of the second material 300, while the overallspunbond-meltblown-spunbond (SMS) laminate arrangement of the secondmaterial contributes to the air breathability of the surgical gown 101.

The various components of the disposable surgical gown 101 of thepersonal protection and ventilation system 100 with which the visorsystem 180 of the present invention can be used are discussed in moredetail below. As an initial matter, it is to be understood that any ofthe spunbond layers, meltblown layers, or elastic film layers of thefirst material 200 and/or the second material 300 can include pigmentsto impart the gown 101 with a gray color, which provides anti-glare andlight reflectance properties, which, in turn, can provide a bettervisual field during surgeries or other procedures where operating roomlighting can result in poor visual conditions, resulting in glare thatcauses visual discomfort, and leads to fatigue of operating room staffduring surgical procedures.

For instance, examples of suitable pigments used to arrive at thedesired gray pigment for the gown include, but are not limited to,titanium dioxide (e.g., SCC 11692 concentrated titanium dioxide),zeolites, kaolin, mica, carbon black, calcium oxide, magnesium oxide,aluminum hydroxide, and combinations thereof. In certain cases, forinstance, each of the various individual layers of the gown materials200 and 300 can include titanium dioxide in an amount ranging from about0.1 wt. % to about 10 wt. %, in some embodiments, from about 0.5 wt. %to about 7.5 wt. %, and in some embodiments, from about 1 wt. % to about5 wt. % based on the total weight of the individual layer. The titaniumdioxide can have a refractive index ranging from about 2.2 to about 3.2,such as from about 2.4 to about 3, such as from about 2.6 to about 2.8,such as about 2.76, to impart the material 200 with the desired lightscattering and light absorbing properties. Further, each of the variousindividual layers of the gown materials 200 and 300 can also includecarbon black in an amount ranging from about 0.1 wt. % to about 10 wt.%, in some embodiments, from about 0.5 wt. % to about 7.5 wt. %, and insome embodiments, from about 1 wt. % to about 5 wt. % based on the totalweight of the individual layer. The carbon black can have a refractiveindex ranging from about 1.2 to about 2.4, such as from about 1.4 toabout 2.2, such as from about 1.6 to about 2 to impart the material 200with the desired light scattering and light absorbing properties. Eachof the various individual layers of the gown materials 200 and 300 canalso include a blue pigment in an amount ranging from about 0.1 wt. % toabout 10 wt. %, in some embodiments, from about 0.5 wt. % to about 7.5wt. %, and in some embodiments, from about 1 wt. % to about 5 wt. %based on the total weight of the individual layer. The combination ofthe carbon black and blue pigment improves the ability of the nonwovenmaterials and film of the present invention to absorb light.

As a result of the incorporation of one or more of the aforementionedpigments into the gown 101 materials, the first material 200 and/or thesecond material 300 can thus be a sufficient shade of gray to preventglare. Gray is an imperfect absorption of the light or a mixture ofblack and white, where it is to be understood that although black,white, and gray are sometimes described as achromatic or hueless colors,a color may be referred to as “black” if it absorbs all frequencies oflight. That is, an object that absorbs all wavelengths of light thatstrike it so that no parts of the spectrum are reflected is consideredto be black. Black is darker than any color on the color wheel orspectrum. In contrast, white is lighter than any color on the colorwheel or spectrum. If an object reflects all wavelengths of lightequally, that object is considered to be white.

As mentioned above, the front panel 102, sleeves 104, and hood 178(e.g., all of the hood 178 or at least the first portion 256 of the hood178 as described above) of the gown 101 can be formed from a firstmaterial 200. The first material 200 can be a stretchable elasticbreathable barrier material that renders the aforementioned sections ofthe gown 101 impervious to bodily fluids and other liquids while stillproviding satisfactory levels of moisture vapor breathability and/ormoisture vapor transmission and stretchabiilty. The first material 200can include a combination of a film, which can serve as the key barrierand elastic component of the surgical gown 101, and one or more nonwovenlayers (e.g., spunbond layers, meltblown layers, a combination thereof,etc.) to provide softness and comfort. The film can be configured toexhibit elastic properties such that the film maintains its fluidbarrier characteristics even when elongated in the machine direction byamounts at least as twice as high as currently available gowns such thatthe gown 101 passes ASTM-1671 “Standard Test Method for Resistance ofMaterials Used in Protective Clothing to Penetration by Blood-BornePathogens Using Phi-X174 Bacteriophage Penetration as a Test System.”Meanwhile, as a result of the inclusion of the nonwoven layers inconjunction with the elastic film, the overall first material 200 canhave an increased bending modulus to achieve the desired pliability andsoftness which results in a material that is comfortable to the wearer.

As discussed above, in one particular embodiment, the first material 200can include an outer spunbond layer 142, a spunbond-meltblown-spunbondlaminate 146, and an elastic film 144 positioned therebetween. The outerspunbond layer 142 can form an outer-facing surface 202 of the frontpanel 102, sleeves 104, and hood 178 of the surgical gown 101, while oneof the spunbond layers of the SMS laminate 146 can form the body-facingsurface or inner-facing surface 204 of the front panel 102, sleeves 104,and hood 178 of the surgical gown 101. Further, the outer spunbond layer142 and one or more layers of the SMS laminate 146 can include a slipadditive to achieve the desired softness, while the film 144 can includea fluorochemical additive to increase the surface energy of the elasticfilm 144 and enhance the ability of the elastic film 144 to serve as abarrier to bodily fluids and tissues, including fatty oils that may begenerated during very invasive surgeries as a result of the macerationof fatty tissue. Each of these components of the first material 200 isdescribed in more detail below.

The outer spunbond layer 142 can be formed from any suitable polymerthat provides softness, stretch, and pliability to the first material200. For instance, the outer spunbond layer 142 can be formed from asemi-crystalline polyolefin. Exemplary polyolefins may include, forinstance, polyethylene, polypropylene, blends and copolymers thereof. Inone particular embodiment, a polyethylene is employed that is acopolymer of ethylene and an α-olefin, such as a C₃-C₂₀ α-olefin orC₃-C₁₂ α-olefin. Suitable α-olefins may be linear or branched (e.g., oneor more C₁-C₃ alkyl branches, or an aryl group). Specific examplesinclude 1-butene; 3-methyl-1-butene; 3,3-dimethyl-1-butene; 1-pentene;1-pentene with one or more methyl, ethyl or propyl substituents;1-hexene with one or more methyl, ethyl or propyl substituents;1-heptene with one or more methyl, ethyl or propyl substituents;1-octene with one or more methyl, ethyl or propyl substituents; 1-nonenewith one or more methyl, ethyl or propyl substituents; ethyl, methyl ordimethyl-substituted 1-decene; 1-dodecene; and styrene. Particularlydesired α-olefin co-monomers are 1-butene, 1-hexene and 1-octene. Theethylene content of such copolymers may be from about 60 mole % to about99 mole %, in some embodiments from about 80 mole % to about 98.5 mole%, and in some embodiments, from about 87 mole % to about 97.5 mole %.The α-olefin content may likewise range from about 1 mole % to about 40mole %, in some embodiments from about 1.5 mole % to about 15 mole %,and in some embodiments, from about 2.5 mole % to about 13 mole %.

The density of the polyethylene may vary depending on the type ofpolymer employed, but generally ranges from 0.85 to 0.96 grams per cubiccentimeter (“g/cm³”). Polyethylene “plastomers”, for instance, may havea density in the range of from 0.85 to 0.91 g/cm³. Likewise, “linear lowdensity polyethylene” (“LLDPE”) may have a density in the range of from0.91 to 0.940 g/cm³; “low density polyethylene” (“LDPE”) may have adensity in the range of from 0.910 to 0.940 g/cm³; and “high densitypolyethylene” (“HDPE”) may have density in the range of from 0.940 to0.960 g/cm³. Densities may be measured in accordance with ASTM 1505.Particularly suitable ethylene-based polymers for use in the presentinvention may be available under the designation EXACT™ from ExxonMobilChemical Company of Houston, Tex. Other suitable polyethylene plastomersare available under the designation ENGAGE™ and AFFINITY™ from DowChemical Company of Midland, Mich. Still other suitable ethylenepolymers are available from The Dow Chemical Company under thedesignations DOWLEX™ (LLDPE) and ATTANE™ (ULDPE). Other suitableethylene polymers are described in U.S. Pat. No. 4,937,299 to Ewen etal.; U.S. Pat. No. 5,218,071 to Tsutsui et al.; U.S. Pat. No. 5,272,236to Lai et al.; and U.S. Pat. No. 5,278,272 to Lai, et al., which areincorporated herein in their entirety by reference thereto for allpurposes.

Of course, the outer spunbond layer 142 of the first material 200 is byno means limited to ethylene polymers. For instance, propylene polymersmay also be suitable for use as a semi-crystalline polyolefin. Suitablepropylene polymers may include, for instance, polypropylenehomopolymers, as well as copolymers or terpolymers of propylene with anα-olefin (e.g., C₃-C₂₀) comonomer, such as ethylene, 1-butene, 2-butene,the various pentene isomers, 1-hexene, 1-octene, 1-nonene, 1-decene,1-unidecene, 1-dodecene, 4-methyl-1-pentene, 4-methyl-1-hexene,5-methyl-1-hexene, vinylcyclohexene, styrene, etc. The comonomer contentof the propylene polymer may be about 35 wt. % or less, in someembodiments from about 1 wt. % to about 20 wt. %, in some embodiments,from about 2 wt. % to about 15 wt. %, and in some embodiments from about3 wt. % to about 10 wt. %. The density of the polypropylene (e.g.,propylene/α-olefin copolymer) may be 0.95 grams per cubic centimeter(g/cm³) or less, in some embodiments, from 0.85 to 0.92 g/cm³, and insome embodiments, from 0.85 g/cm³ to 0.91 g/cm³. In one particularembodiment, the outer spunbond layer 142 can include a copolymer ofpolypropylene and polyethylene. The polypropylene can have a refractiveindex ranging from about 1.44 to about 1.54, such as from about 1.46 toabout 1.52, such as from about 1.48 to about 1.50, such as about 1.49,while the polyethylene can have a refractive index ranging from about1.46 to about 1.56, such as from about 1.48 to about 1.54, such as fromabout 1.50 to about 1.52, such as about 1.51, to impart the material 200with the desired light scattering and light absorbing properties.

Suitable propylene polymers are commercially available under thedesignations VISTAMAXX™ from ExxonMobil Chemical Co. of Houston, Tex.;FINA™ (e.g., 8573) from Atofina Chemicals of Feluy, Belgium; TAFMER™available from Mitsui Petrochemical Industries; and VERSIFY™ availablefrom Dow Chemical Co. of Midland, Mich. Other examples of suitablepropylene polymers are described in U.S. Pat. No. 6,500,563 to Datta, etal.; U.S. Pat. No. 5,539,056 to Yang, et al.; and U.S. Pat. No.5,596,052 to Resconi, et al., which are incorporated herein in theirentirety by reference thereto for all purposes.

Any of a variety of known techniques may generally be employed to formthe polyolefins. For instance, olefin polymers may be formed using afree radical or a coordination catalyst (e.g., Ziegler-Natta ormetallocene). Metallocene-catalyzed polyolefins are described, forinstance, in U.S. Pat. No. 5,571,619 to McAlpin et at; U.S. Pat. No.5,322,728 to Davis et al.; U.S. Pat. No. 5,472,775 to Obijeski et al.;U.S. Pat. No. 5,272,236 to Lai et al.; and U.S. Pat. No. 6,090,325 toWheat, et al., which are incorporated herein in their entirety byreference thereto for all purposes.

The melt flow index (MI) of the polyolefins may generally vary, but istypically in the range of about 0.1 grams per 10 minutes to about 100grams per 10 minutes, in some embodiments from about 0.5 grams per 10minutes to about 30 grams per 10 minutes, and in some embodiments, about1 to about 10 grams per 10 minutes, determined at 190° C. The melt flowindex is the weight of the polymer (in grams) that may be forced throughan extrusion rheometer orifice (0.0825-inch diameter) when subjected toa force of 2160 grams in 10 minutes at 190° C., and may be determined inaccordance with ASTM Test Method D1238-E.

In addition to a polyolefin, the outer spunbond layer 142 can alsoinclude a slip additive to enhance the softness of the outer spunbondlayer 142. The slip additive can also reduce the coefficient of frictionand increase the hydrohead of the outer spunbond layer 142 of the frontpanel 102 and the sleeves 104. Such a reduction in the coefficient offriction lessens the chance of the gown 101 being cut or damaged due toabrasions and also prevents fluids from seeping through the firstmaterial 200. Instead, at least in part due to the inclusion of the slipadditive, fluid that contacts the outer-facing surface 202 of the gown101 can remain in droplet form and run vertically to the distal end 156of the gown 101 and onto the floor. The slip additive can also reducethe glare of the first material 200 in the operating room by reducingthe light reflectance of the first material and can also render thefirst material 200 more opaque than the standard gown material whencontacted with fats and lipids during surgery, where the standard gownmaterial turns transparent upon contact with fats and lipids, which canresult in the wearer having some concern that the barrier properties ofa standard gown have been compromised.

The slip additive can function by migrating to the surface of thepolymer used to form the outer spunbond layer 142, where it can providea coating that reduces the coefficient of friction of the outer-facingsurface 202 of the first material 200. Variants of fatty acids can beused as slip additives. For example, the slip additive can be erucamide,oleamide, stearamide, behenamide, oleyl palmitamide, stearyl erucamide,ethylene bis-oleamide, N,N′-Ethylene Bis(Stearamide) (EBS), or acombination thereof. Further, the slip additive have a refractive indexranging from about 1.42 to about 1.52, such as from about 1.44 to about1.50, such as from about 1.46 to about 1.48, such as about 1.47, toimpart the material 200 with the desired light scattering and lightabsorbing properties by reducing the refractive index. The slip additivecan be present in the outer spunbond layer 142 in an amount ranging fromabout 0.1 wt. % to about 4 wt. %, such as from about 0.25 wt. % to about3 wt. %, such as from about 0.5 wt. % to about 2 wt. % based on thetotal weight of the outer spunbond layer 142. In one particularembodiment, the slip additive can be present in an amount of about 1 wt.% based on the total weight of the outer spunbond layer 142.

In addition to the polyolefin and slip additive, the outer spunbondlayer 142 can also include one or more pigments to help achieve thedesired gray color of the gown 101. Examples of suitable pigmentsinclude, but are not limited to, titanium dioxide (e.g., SCC 11692concentrated titanium dioxide), zeolites, kaolin, mica, carbon black,calcium oxide, magnesium oxide, aluminum hydroxide, and combinationsthereof. In certain cases, for instance, the outer spunbond layer 142can include titanium dioxide in an amount ranging from about 0.1 wt. %to about 10 wt. %, in some embodiments, from about 0.5 wt. % to about7.5 wt. %, and in some embodiments, from about 1 wt. % to about 5 wt. %based on the total weight of the outer spunbond layer 142. The titaniumdioxide can have a refractive index ranging from about 2.2 to about 3.2,such as from about 2.4 to about 3, such as from about 2.6 to about 2.8,such as about 2.76, to impart the material 200 with the desired lightscattering and light absorbing properties. Further, the outer spunbondlayer 142 can also include carbon black in an amount ranging from about0.1 wt. % to about 10 wt. %, in some embodiments, from about 0.5 wt. %to about 7.5 wt. %, and in some embodiments, from about 1 wt. % to about5 wt. % based on the total weight of the outer spunbond layer 142. Thecarbon black can have a refractive index ranging from about 1.2 to about2.4, such as from about 1.4 to about 2.2, such as from about 1.6 toabout 2 to impart the material 200 with the desired light scattering andlight absorbing properties. The outer spunbond layer 142 can alsoinclude a blue pigment in an amount ranging from about 0.1 wt. % toabout 10 wt. %, in some embodiments, from about 0.5 wt. % to about 7.5wt. %, and in some embodiments, from about 1 wt. % to about 5 wt. %based on the total weight of the individual layer. The combination ofthe carbon black and blue pigment improves the ability of the outerspunbond layer 142 to absorb light.

Regardless of the specific polymer or polymers and additives used toform the outer spunbond layer 142, the outer spunbond layer 142 can havea basis weight ranging from about 5 gsm to about 50 gsm, such as fromabout 10 gsm to about 40 gsm, such as from about 15 gsm to about 30 gsm.In one particular embodiment, the outer spunbond layer 142 can have abasis weight of about 20 gsm (about 0.6 osy).

The elastic film 144 of the first material 200 can be formed from anysuitable polymer or polymers that are capable of acting as a barriercomponent in that it is generally impervious, while at the same timeproviding moisture vapor breathability to the first material 200. Theelastic film 144 can be formed from one or more layers of polymers thatare melt-processable, i.e., thermoplastic. In one particular embodiment,the elastic film 144 can be a monolayer film. If the film is amonolayer, any of the polymers discussed below in can be used to formthe monolayer. In other embodiments, the elastic film 144 can includetwo, three, four, five, six, or seven layers, where each of the layerscan be formed from any of the polymers discussed below, where the one ormore layers are formed from the same or different materials. Forinstance, in one particular embodiment the elastic film 144 can includea core layer 144B disposed between two skin layers, 144A and 144C. Eachof these components of the film are discussed in more detail below.

First, the elastic film core layer 144B can be formed from one or moresemi-crystalline polyolefins. Exemplary semi-crystalline polyolefinsinclude polyethylene, polypropylene, blends and copolymers thereof. Inone particular embodiment, a polyethylene is employed that is acopolymer of ethylene and an α-olefin, such as a C₃-C₂₀ α-olefin orC₃-C₁₂ α-olefin. Suitable α-olefins may be linear or branched (e.g., oneor more C₁-C₃ alkyl branches, or an aryl group). Specific examplesinclude 1-butene; 3-methyl-1-butene; 3,3-dimethyl-1-butene; 1-pentene;1-pentene with one or more methyl, ethyl or propyl substituents;1-hexene with one or more methyl, ethyl or propyl substituents;1-heptene with one or more methyl, ethyl or propyl substituents;1-octene with one or more methyl, ethyl or propyl substituents; 1-nonenewith one or more methyl, ethyl or propyl substituents; ethyl, methyl ordimethyl-substituted 1-decene; 1-dodecene; and styrene. Particularlydesired α-olefin comonomers are 1-butene, 1-hexene and 1-octene. Theethylene content of such copolymers may be from about 60 mole % to about99 mole %, in some embodiments from about 80 mole % to about 98.5 mole%, and in some embodiments, from about 87 mole % to about 97.5 mole %.The α-olefin content may likewise range from about 1 mole % to about 40mole %, in some embodiments from about 1.5 mole % to about 15 mole %,and in some embodiments, from about 2.5 mole % to about 13 mole %.

Particularly suitable polyethylene copolymers are those that are“linear” or “substantially linear.” The term “substantially linear”means that, in addition to the short chain branches attributable tocomonomer incorporation, the ethylene polymer also contains long chainbranches in the polymer backbone. “Long chain branching” refers to achain length of at least 6 carbons. Each long chain branch may have thesame comonomer distribution as the polymer backbone and be as long asthe polymer backbone to which it is attached. Preferred substantiallylinear polymers are substituted with from 0.01 long chain branch per1000 carbons to 1 long chain branch per 1000 carbons, and in someembodiments, from 0.05 long chain branch per 1000 carbons to 1 longchain branch per 1000 carbons. In contrast to the term “substantiallylinear”, the term “linear” means that the polymer lacks measurable ordemonstrable long chain branches. That is, the polymer is substitutedwith an average of less than 0.01 long chain branch per 1000 carbons.

The density of a linear ethylene/α-olefin copolymer is a function ofboth the length and amount of the α-olefin. That is, the greater thelength of the α-olefin and the greater the amount of α-olefin present,the lower the density of the copolymer. Although not necessarilyrequired, linear polyethylene “plastomers” are particularly desirable inthat the content of α-olefin short chain branching content is such thatthe ethylene copolymer exhibits both plastic and elastomericcharacteristics—i.e., a “plastomer.” Because polymerization withα-olefin comonomers decreases crystallinity and density, the resultingplastomer normally has a density lower than that of a polyethylenethermoplastic polymer (e.g., LLDPE), which typically has a density(specific gravity) of from about 0.90 grams per cubic centimeter (g/cm³)to about 0.94 g/cm³, but approaching and/or overlapping that of anelastomer, which typically has a density of from about 0.85 g/cm³ toabout 0.90 g/cm³, preferably from 0.86 to 0.89. For example, the densityof the polypropylene (e.g., propylene/α-olefin copolymer) may be 0.95grams per cubic centimeter (g/cm³) or less, in some embodiments, from0.85 to 0.92 g/cm³, and in some embodiments, from 0.85 g/cm³ to 0.91g/cm³. Despite having a density similar to elastomers, plastomersgenerally exhibit a higher degree of crystallinity, are relativelynon-tacky, and may be formed into pellets that are non-adhesive-like andrelatively free flowing.

Preferred polyethylenes for use in the present invention areethylene-based copolymer plastomers available under the designationEXACT™ from ExxonMobil Chemical Company of Houston, Tex. Other suitablepolyethylene plastomers are available under the designation ENGAGE™ andAFFINITY™ from Dow Chemical Company of Midland, Mich. An additionalsuitable polyethylene-based plastomer is an olefin block copolymeravailable from Dow Chemical Company of Midland, Mich. under the tradedesignation INFUSE™, which is an elastomeric copolymer of polyethylene.Still other suitable ethylene polymers are low density polyethylenes(LDPE), linear low density polyethylenes (LLDPE) or ultralow lineardensity polyethylenes (ULDPE), such as those available from The DowChemical Company under the designations ASPUN™ (LLDPE), DOWLEX™ (LLDPE)and ATTANE™ (ULDPE). Other suitable ethylene polymers are described inU.S. Pat. No. 4,937,299 to Ewen, et al., U.S. Pat. No. 5,218,071 toTsutsui et al., U.S. Pat. No. 5,272,236 to Lai et al., and U.S. Pat. No.5,278,272 to Lai, et al., which are incorporated herein in theirentirety by reference thereto for all purposes.

Of course, the elastic film core layer 144B of the present invention isby no means limited to ethylene polymers. For instance, propyleneplastomers may also be suitable for use in the film. Suitableplastomeric propylene polymers may include, for instance, polypropylenehomopolymers, copolymers or terpolymers of propylene, copolymers ofpropylene with an α-olefin (e.g., C₃-C₂₀) comonomer, such as ethylene,1-butene, 2-butene, the various pentene isomers, 1-hexene, 1-octene,1-nonene, 1-decene, 1-unidecene, 1-dodecene, 4-methyl-1-pentene,4-methyl-1-hexene, 5-methyl-1-hexene, vinylcyclohexene, styrene, etc.The comonomer content of the propylene polymer may be about 35 wt. % orless, in some embodiments from about 1 wt. % to about 20 wt. %, in someembodiments from about 2 wt. % to about 15 wt. %, and in someembodiments from about 3 wt. % to about 10 wt. %. Preferably, thedensity of the polypropylene (e.g., propylene/α-olefin copolymer) may be0.95 grams per cubic centimeter (g/cm³) or less, in some embodiments,from 0.85 to 0.92 g/cm³, and in some embodiments, from 0.85 g/cm³ to0.91 g/cm³.

Suitable propylene polymers are commercially available under thedesignations VISTAMAXX™ (e.g., 6102), a propylene-based elastomer fromExxonMobil Chemical Co. of Houston, Tex.; FINA™ (e.g., 8573) fromAtofina Chemicals of Feluy, Belgium; TAFMER™ available from MitsuiPetrochemical Industries; and VERSIFY™ available from Dow Chemical Co.of Midland, Mich. Other examples of suitable propylene polymers aredescribed in U.S. Pat. No. 5,539,056 to Yang, et al., U.S. Pat. No.5,596,052 to Resconi, et al., and U.S. Pat. No. 6,500,563 to Datta, etal., which are incorporated herein in their entirety by referencethereto for all purposes. In one particular embodiment, the elastic filmcore layer 144B includes polypropylene. The polypropylene can have arefractive index ranging from about 1.44 to about 1.54, such as fromabout 1.46 to about 1.52, such as from about 1.48 to about 1.50, such asabout 1.49 to help impart the material 200 with the desired lightscattering and light absorbing properties.

Any of a variety of known techniques may generally be employed to formthe semi-crystalline polyolefins. For instance, olefin polymers may beformed using a free radical or a coordination catalyst (e.g.,Ziegler-Natta). Preferably, the olefin polymer is formed from asingle-site coordination catalyst, such as a metallocene catalyst. Sucha catalyst system produces ethylene copolymers in which the comonomer israndomly distributed within a molecular chain and uniformly distributedacross the different molecular weight fractions. Metallocene-catalyzedpolyolefins are described, for instance, in U.S. Pat. No. 5,272,236 toLai et al., U.S. Pat. No. 5,322,728 to Davis et al., U.S. Pat. No.5,472,775 to Obijeski et al., U.S. Pat. No. 5,571,619 to McAlpin et al.,and U.S. Pat. No. 6,090,325 to Wheat, et al., which are incorporatedherein in their entirety by reference thereto for all purposes. Examplesof metallocene catalysts include bis(n-butylcyclopentadienyl)titaniumdichloride, bis(n-butylcyclopentadienyl)zirconium dichloride,bis(cyclopentadienyl)scandium chloride, bis(indenyl)zirconiumdichloride, bis(methylcyclopentadienyl)titanium dichloride,bis(methylcyclopentadienyl) zirconium dichloride, cobaltocene,cyclopentadienyltitanium trichloride, ferrocene, hafnocene dichloride,isopropyl(cyclopentadienyl,-1-flourenyl)zirconium dichloride,molybdocene dichloride, nickelocene, niobocene dichloride, ruthenocene,titanocene dichloride, zirconocene chloride hydride, zirconocenedichloride, and so forth. Polymers made using metallocene catalyststypically have a narrow molecular weight range. For instance,metallocene-catalyzed polymers may have polydispersity numbers(M_(w)/M_(n)) of below 4, controlled short chain branching distribution,and controlled isotacticity.

The melt flow index (MI) of the semi-crystalline polyolefins maygenerally vary, but is typically in the range of about 0.1 grams per 10minutes to about 100 grams per 10 minutes, in some embodiments fromabout 0.5 grams per 10 minutes to about 30 grams per 10 minutes, and insome embodiments, about 1 to about 10 grams per 10 minutes, determinedat 190° C. The melt flow index is the weight of the polymer (in grams)that may be forced through an extrusion rheometer orifice (0.0825-inchdiameter) when subjected to a force of 5000 grams in 10 minutes at 190°C., and may be determined in accordance with ASTM Test Method D1238-E.

In addition to a polyolefin such as polypropylene, the elastic film corelayer 144B can also include a fluorochemical additive to increase thesurface energy of the elastic film 144, which, in turn, increases theimperviousness of the elastic film 144 to bodily fluids and biologicmaterials such as fatty oils that may be generated during very invasivesurgeries. One example of a fluorochemical additive contemplated for usein the core layer 144B is a fluoroalkyl acrylate copolymer such asUnidyne® TG from Daikin. The fluorochemical additive can have arefractive index that is less than about 1.4 in order to lower therefractive index of the elastic film core layer 144B. For instance, thefluorochemical additive can have a refractive index ranging from about1.2 to about 1.4, such as from about 1.22 to about 1.38, such as fromabout 1.24 to about 1.36. Without intending to be limited by anyparticular theory, it is believed that the fluorochemical additivesegregates to the surface of the polyolefin film, where a lowerrefractive index region is formed, which enhances light scattering ofthe film as compared to films that are free of a fluorochemicaladditive. Regardless of the particular fluorochemical additive utilized,the fluorochemical additive can be present in the elastic film corelayer 144B in an amount ranging from about 0.1 wt. % to about 5 wt. %,such as from about 0.5 wt. % to about 4 wt. %, such as from about 1 wt.% to about 3 wt. % based on the total weight of the elastic film corelayer 144B. In one particular embodiment, the fluorochemical additivecan be present in an amount of about 1.5 wt. % based on the total weightof the elastic film core layer 144B.

In one embodiment, the elastic film core layer 144B can also include afiller. Fillers are particulates or other forms of material that may beadded to the film polymer extrusion blend and that will not chemicallyinterfere with the extruded film, but which may be uniformly dispersedthroughout the film. Fillers may serve a variety of purposes, includingenhancing film opacity and/or breathability (i.e., vapor-permeable andsubstantially liquid-impermeable). For instance, filled films may bemade breathable by stretching, which causes the polymer to break awayfrom the filler and create microporous passageways. Breathablemicroporous elastic films are described, for example, in U.S. Pat. No.5,932,497 to Morman, et al., U.S. Pat. Nos. 5,997,981, 6,015,764, and6,111,163 to McCormack, et al., and U.S. Pat. No. 6,461,457 to Taylor,et al., which are incorporated herein in their entirety by referencethereto for all purposes. Examples of suitable fillers include, but arenot limited to, calcium carbonate, various kinds of clay, silica,alumina, barium carbonate, sodium carbonate, magnesium carbonate, talc,barium sulfate, magnesium sulfate, aluminum sulfate, zeolites,cellulose-type powders, kaolin, mica, carbon, calcium oxide, magnesiumoxide, aluminum hydroxide, pulp powder, wood powder, cellulosederivatives, chitin and chitin derivatives. In one particularembodiment, the filler in the core layer 144B can include calciumcarbonate, which can provide the elastic film 144, and thus the material200, with light scattering and light absorbing properties to help reduceglare, particularly after stretching the calcium carbonate-containingcore layer 144B, which further increases the opacity and increases thelight scattering of the material 200. For instance, the calciumcarbonate (or any other suitable filler) can have a refractive indexranging from about 1.60 to about 1.72, such as from about 1.62 to about1.70, such as from about 1.64 to about 1.68, such as about 1.66, toimpart the material 200 with the desired light scattering and lightabsorbing properties. In certain cases, the filler content of the filmmay range from about 50 wt. % to about 85 wt. %, in some embodiments,from about 55 wt. % to about 80 wt. %, and in some embodiments, fromabout 60 wt. % to about 75 wt. % of the elastic film core layer 1446based on the total weight of the elastic film core layer 144B.

Further, the elastic film core layer 1446 can also include one or morepigments to help achieve the desired gray color of the gown 101.Examples of suitable pigments include, but are not limited to, titaniumdioxide (e.g., SCC 11692 concentrated titanium dioxide), zeolites,kaolin, mica, carbon black, calcium oxide, magnesium oxide, aluminumhydroxide, and combinations thereof. In certain cases, for instance, theelastic film core layer 144B can include titanium dioxide in an amountranging from about 0.1 wt. % to about 10 wt. %, in some embodiments,from about 0.5 wt. % to about 7.5 wt. %, and in some embodiments, fromabout 1 wt. % to about 5 wt. % based on the total weight of the corelayer 144B. The titanium dioxide can have a refractive index rangingfrom about 2.2 to about 3.2, such as from about 2.4 to about 3, such asfrom about 2.6 to about 2.8, such as about 2.76, to impart the material200 with the desired light scattering and light absorbing properties.Further, the elastic film core layer 1446 can also include carbon blackin an amount ranging from about 0.1 wt. % to about 10 wt. %, in someembodiments, from about 0.5 wt. % to about 7.5 wt. %, and in someembodiments, from about 1 wt. % to about 5 wt. % based on the totalweight of the core layer 144B. The carbon black can have a refractiveindex ranging from about 1.2 to about 2.4, such as from about 1.4 toabout 2.2, such as from about 1.6 to about 2 to impart the material 200with the desired light scattering and light absorbing properties. Theelastic film core layer 144B can also include a blue pigment in anamount ranging from about 0.1 wt. % to about 10 wt. %, in someembodiments, from about 0.5 wt. % to about 7.5 wt. %, and in someembodiments, from about 1 wt. % to about 5 wt. % based on the totalweight of the individual layer. The combination of the carbon black andblue pigment improves the ability of the elastic film core layer 144B toabsorb light.

Further, like the elastic film core layer 144B, the elastic film skinlayers 144A and 144C that sandwich the elastic film core layer 1446 canalso be formed from one or more semi-crystalline polyolefins. Exemplarysemi-crystalline polyolefins include polyethylene, polypropylene, blendsand copolymers thereof. In one particular embodiment, a polyethylene isemployed that is a copolymer of ethylene and an α-olefin, such as aC₃-C₂₀ α-olefin or C₃-C₁₂ α-olefin. Suitable α-olefins may be linear orbranched (e.g., one or more C₁-C₃ alkyl branches, or an aryl group).Specific examples include 1-butene; 3-methyl-1-butene;3,3-dimethyl-1-butene; 1-pentene; 1-pentene with one or more methyl,ethyl or propyl substituents; 1-hexene with one or more methyl, ethyl orpropyl substituents; 1-heptene with one or more methyl, ethyl or propylsubstituents; 1-octene with one or more methyl, ethyl or propylsubstituents; 1-nonene with one or more methyl, ethyl or propylsubstituents; ethyl, methyl or dimethyl-substituted 1-decene;1-dodecene; and styrene. Particularly desired α-olefin comonomers are1-butene, 1-hexene and 1-octene. The ethylene content of such copolymersmay be from about 60 mole % to about 99 mole %, in some embodiments fromabout 80 mole % to about 98.5 mole %, and in some embodiments, fromabout 87 mole % to about 97.5 mole %. The α-olefin content may likewiserange from about 1 mole % to about 40 mole %, in some embodiments fromabout 1.5 mole % to about 15 mole %, and in some embodiments, from about2.5 mole % to about 13 mole %.

Particularly suitable polyethylene copolymers are those that are“linear” or “substantially linear.” The term “substantially linear”means that, in addition to the short chain branches attributable tocomonomer incorporation, the ethylene polymer also contains long chainbranches in the polymer backbone. “Long chain branching” refers to achain length of at least 6 carbons. Each long chain branch may have thesame comonomer distribution as the polymer backbone and be as long asthe polymer backbone to which it is attached. Preferred substantiallylinear polymers are substituted with from 0.01 long chain branch per1000 carbons to 1 long chain branch per 1000 carbons, and in someembodiments, from 0.05 long chain branch per 1000 carbons to 1 longchain branch per 1000 carbons. In contrast to the term “substantiallylinear”, the term “linear” means that the polymer lacks measurable ordemonstrable long chain branches. That is, the polymer is substitutedwith an average of less than 0.01 long chain branch per 1000 carbons.

The density of a linear ethylene/α-olefin copolymer is a function ofboth the length and amount of the α-olefin. That is, the greater thelength of the α-olefin and the greater the amount of α-olefin present,the lower the density of the copolymer. Although not necessarilyrequired, linear polyethylene “plastomers” are particularly desirable inthat the content of α-olefin short chain branching content is such thatthe ethylene copolymer exhibits both plastic and elastomericcharacteristics—i.e., a “plastomer.” Because polymerization withα-olefin comonomers decreases crystallinity and density, the resultingplastomer normally has a density lower than that of a polyethylenethermoplastic polymer (e.g., LLDPE), which typically has a density(specific gravity) of from about 0.90 grams per cubic centimeter (g/cm³)to about 0.94 g/cm³, but approaching and/or overlapping that of anelastomer, which typically has a density of from about 0.85 g/cm³ toabout 0.90 g/cm³, preferably from 0.86 to 0.89. For example, the densityof the polyethylene plastomer may be 0.91 g/cm³ or less, in someembodiments from about 0.85 g/cm³ to about 0.90 g/cm³, in someembodiments, from 0.85 g/cm³ to 0.88 g/cm³, and in some embodiments,from 0.85 g/cm³ to 0.87 g/cm³. Despite having a density similar toelastomers, plastomers generally exhibit a higher degree ofcrystallinity, are relatively non-tacky, and may be formed into pelletsthat are non-adhesive-like and relatively free flowing.

Preferred polyethylenes for use in the present invention areethylene-based copolymer plastomers available under the designationEXACT™ from ExxonMobil Chemical Company of Houston, Tex. Other suitablepolyethylene plastomers are available under the designation ENGAGE™ andAFFINITY™ from Dow Chemical Company of Midland, Mich. An additionalsuitable polyethylene-based plastomer is an olefin block copolymeravailable from Dow Chemical Company of Midland, Mich. under the tradedesignation INFUSE™, which is an elastomeric copolymer of polyethylene.Still other suitable ethylene polymers are low density polyethylenes(LDPE), linear low density polyethylenes (LLDPE) or ultralow lineardensity polyethylenes (ULDPE), such as those available from The DowChemical Company under the designations ASPUN™ (LLDPE), DOWLEX™ (LLDPE)and ATTANE™ (ULDPE). Other suitable ethylene polymers are described inU.S. Pat. No. 4,937,299 to Ewen, et al., U.S. Pat. No. 5,218,071 toTsutsui et al., U.S. Pat. No. 5,272,236 to Lai et al., and U.S. Pat. No.5,278,272 to Lai, et al., which are incorporated herein in theirentirety by reference thereto for all purposes.

Of course, the elastic film skin layers 144A and 144C of the presentinvention are by no means limited to ethylene polymers. For instance,propylene plastomers may also be suitable for use in the film. Suitableplastomeric propylene polymers may include, for instance, polypropylenehomopolymers, copolymers or terpolymers of propylene, copolymers ofpropylene with an α-olefin (e.g., C₃-C₂₀) comonomer, such as ethylene,1-butene, 2-butene, the various pentene isomers, 1-hexene, 1-octene,1-nonene, 1-decene, 1-unidecene, 1-dodecene, 4-methyl-1-pentene,4-methyl-1-hexene, 5-methyl-1-hexene, vinylcyclohexene, styrene, etc.The comonomer content of the propylene polymer may be about 35 wt. % orless, in some embodiments from about 1 wt. % to about 20 wt. %, in someembodiments from about 2 wt. % to about 15 wt. %, and in someembodiments from about 3 wt. % to about 10 wt. %. The density of thepolypropylene (e.g., propylene/α-olefin copolymer) may be 0.95 grams percubic centimeter (g/cm³) or less, in some embodiments, from 0.85 to 0.92g/cm³, and in some embodiments, from 0.85 g/cm³ to 0.91 g/cm³. In oneparticular embodiment, the elastic film skin layers 144A and 144C caninclude a copolymer of polypropylene and polyethylene. The polypropylenecan have a refractive index ranging from about 1.44 to about 1.54, suchas from about 1.46 to about 1.52, such as from about 1.48 to about 1.50,such as about 1.49, while the polyethylene can have a refractive indexranging from about 1.46 to about 1.56, such as from about 1.48 to about1.54, such as from about 1.50 to about 1.52, such as about 1.51, toimpart the material 200 with the desired light scattering and lightabsorbing properties.

Suitable propylene polymers are commercially available under thedesignations VISTAMAXX™ (e.g., 6102), a propylene-based elastomer fromExxonMobil Chemical Co. of Houston, Tex.; FINA™ (e.g., 8573) fromAtofina Chemicals of Feluy, Belgium; TAFMER™ available from MitsuiPetrochemical Industries; and VERSIFY™ available from Dow Chemical Co.of Midland, Mich. Other examples of suitable propylene polymers aredescribed in U.S. Pat. No. 5,539,056 to Yang, et al., U.S. Pat. No.5,596,052 to Resconi, et al., and U.S. Pat. No. 6,500,563 to Datta, etat, which are incorporated herein in their entirety by reference theretofor all purposes.

Any of a variety of known techniques may generally be employed to formthe semi-crystalline polyolefins. For instance, olefin polymers may beformed using a free radical or a coordination catalyst (e.g.,Ziegler-Natta). Preferably, the olefin polymer is formed from asingle-site coordination catalyst, such as a metallocene catalyst. Sucha catalyst system produces ethylene copolymers in which the comonomer israndomly distributed within a molecular chain and uniformly distributedacross the different molecular weight fractions. Metallocene-catalyzedpolyolefins are described, for instance, in U.S. Pat. No. 5,272,236 toLai et al., U.S. Pat. No. 5,322,728 to Davis et al., U.S. Pat. No.5,472,775 to Obiieski et al., U.S. Pat. No. 5,571,619 to McAlpin et al.,and U.S. Pat. No. 6,090,325 to Wheat, et al., which are incorporatedherein in their entirety by reference thereto for all purposes. Examplesof metallocene catalysts include bis(n-butylcyclopentadienyl)titaniumdichloride, bis(n-butylcyclopentadienyl)zirconium dichloride,bis(cyclopentadienyl)scandium chloride, bis(indenyl)zirconiumdichloride, bis(methylcyclopentadienyl)titanium dichloride,bis(methylcyclopentadienyl) zirconium dichloride, cobaltocene,cyclopentadienyltitanium trichloride, ferrocene, hafnocene dichloride,isopropyl(cyclopentadienyl,-1-flourenyl)zirconium dichloride,molybdocene dichloride, nickelocene, niobocene dichloride, ruthenocene,titanocene dichloride, zirconocene chloride hydride, zirconocenedichloride, and so forth. Polymers made using metallocene catalyststypically have a narrow molecular weight range. For instance,metallocene-catalyzed polymers may have polydispersity numbers(M_(w)/M_(n)) of below 4, controlled short chain branching distribution,and controlled isotacticity.

The melt flow index (MI) of the semi-crystalline polyolefins maygenerally vary, but is typically in the range of about 0.1 grams per 10minutes to about 100 grams per 10 minutes, in some embodiments fromabout 0.5 grams per 10 minutes to about 30 grams per 10 minutes, and insome embodiments, about 1 to about 10 grams per 10 minutes, determinedat 190° C. The melt flow index is the weight of the polymer (in grams)that may be forced through an extrusion rheometer orifice (0.0825-inchdiameter) when subjected to a force of 5000 grams in 10 minutes at 190°C., and may be determined in accordance with ASTM Test Method D1238-E.

In addition, it is noted that the elastic film skin layers 144A and 144Care free of the fluorochemical additive that is present in the elasticfilm core layer 144B. As a result, the skin layers 144A and 144C have ahigher refractive index than the elastic film core layer 144B, as thefluorochemical additive tends to lower the refractive index of the corelayer 144B. The resulting difference in refractive indices at theinterfaces between the core layer 1446 and the skin layers 144A and 144Cof the elastic film 144 is thought to enhance light scattering, whichcan result in a high level of opacity and a low level of lightreflection (e.g., reduced glare).

In any event, regardless of the number of layers present in the elasticfilm 144 and regardless of the specific polymer or polymers andadditives used to form the elastic film 144, the elastic film 144 canhave a basis weight ranging from about 5 gsm to about 50 gsm, such asfrom about 10 gsm to about 40 gsm, such as from about 15 gsm to about 30gsm. In one particular embodiment, the elastic film 144 can have a basisweight of about 20 gsm (about 0.6 osy).

The first material 200 also includes an SMS laminate 146 that isattached to the skin layer 144C of the elastic film 144. One of thespunbond layers 146C of the SMS laminate 146 can form the inner-facingsurface 204 of the first material 200 of the gown 101, which is used toform the front panel 102 on the front 158 of the gown 101, the sleeves104 and the hood 178. Further, it is to be understood that the spunbondlayer 146A, which is adjacent the skin layer 144C, the spunbond layer146C, and the meltblown layer 146B disposed therebetween can be formedfrom any of the polymers (e.g., polyolefins) mentioned above withrespect to the outer spunbond layer 142. In other words, the SMSlaminate 146 can be formed from any suitable polymer that providessoftness, stretch, and pliability to the first material 200.

In one particular embodiment, the SMS laminate 146 can include a firstspunbond layer 146A and a second spunbond layer 146C, where the spunbondlayers 146A and 146C can be formed from any suitable polymer thatprovides softness, stretch, and pliability to the first material 200.For instance, the spunbond layers 146A and 146C can be formed from asemi-crystalline polyolefin. Exemplary polyolefins may include, forinstance, polyethylene, polypropylene, blends and copolymers thereof. Inone particular embodiment, a polyethylene is employed that is acopolymer of ethylene and an α-olefin, such as a C₃-C₂₀ α-olefin orC₃-C₁₂ α-olefin. Suitable α-olefins may be linear or branched (e.g., oneor more C₁-C₃ alkyl branches, or an aryl group). Specific examplesinclude 1-butene; 3-methyl-1-butene; 3,3-dimethyl-1-butene; 1-pentene;1-pentene with one or more methyl, ethyl or propyl substituents;1-hexene with one or more methyl, ethyl or propyl substituents;1-heptene with one or more methyl, ethyl or propyl substituents;1-octene with one or more methyl, ethyl or propyl substituents; 1-nonenewith one or more methyl, ethyl or propyl substituents; ethyl, methyl ordimethyl-substituted 1-decene; 1-dodecene; and styrene. Particularlydesired α-olefin co-monomers are 1-butene, 1-hexene and 1-octene. Theethylene content of such copolymers may be from about 60 mole % to about99 mole %, in some embodiments from about 80 mole % to about 98.5 mole%, and in some embodiments, from about 87 mole % to about 97.5 mole %.The α-olefin content may likewise range from about 1 mole % to about 40mole %, in some embodiments from about 1.5 mole % to about 15 mole %,and in some embodiments, from about 2.5 mole % to about 13 mole %.

The density of the polyethylene may vary depending on the type ofpolymer employed, but generally ranges from 0.85 to 0.96 grams per cubiccentimeter (“g/cm³”). Polyethylene “plastomers”, for instance, may havea density in the range of from 0.85 to 0.91 g/cm³. Likewise, “linear lowdensity polyethylene” (“LLDPE”) may have a density in the range of from0.91 to 0.940 g/cm³; “low density polyethylene” (“LDPE”) may have adensity in the range of from 0.910 to 0.940 g/cm³; and “high densitypolyethylene” (“HDPE”) may have density in the range of from 0.940 to0.960 g/cm³. Densities may be measured in accordance with ASTM 1505.Particularly suitable ethylene-based polymers for use in the presentinvention may be available under the designation EXACT™ from ExxonMobilChemical Company of Houston, Tex. Other suitable polyethylene plastomersare available under the designation ENGAGE™ and AFFINITY™ from DowChemical Company of Midland, Mich. Still other suitable ethylenepolymers are available from The Dow Chemical Company under thedesignations DOWLEX™ (LLDPE) and ATTANE™ (ULDPE). Other suitableethylene polymers are described in U.S. Pat. No. 4,937,299 to Ewen etal.; U.S. Pat. No. 5,218,071 to Tsutsui et al.; U.S. Pat. No. 5,272,236to Lai et al.; and U.S. Pat. No. 5,278,272 to Lai, et al., which areincorporated herein in their entirety by reference thereto for allpurposes.

Of course, the spunbond layers 146A and 146C of the first material 200are by no means limited to ethylene polymers. For instance, propylenepolymers may also be suitable for use as a semi-crystalline polyolefin.Suitable propylene polymers may include, for instance, polypropylenehomopolymers, as well as copolymers or terpolymers of propylene with anα-olefin (e.g., C₃-C₂₀) comonomer, such as ethylene, 1-butene, 2-butene,the various pentene isomers, 1-hexene, 1-octene, 1-nonene, 1-decene,1-unidecene, 1-dodecene, 4-methyl-1-pentene, 4-methyl-1-hexene,5-methyl-1-hexene, vinylcyclohexene, styrene, etc. The comonomer contentof the propylene polymer may be about 35 wt. % or less, in someembodiments from about 1 wt. % to about 20 wt. %, in some embodiments,from about 2 wt. % to about 15 wt. %, and in some embodiments from about3 wt. % to about 10 wt. %. The density of the polypropylene (e.g.,propylene/α-olefin copolymer) may be 0.95 grams per cubic centimeter(g/cm³) or less, in some embodiments, from 0.85 to 0.92 g/cm³, and insome embodiments, from 0.85 g/cm³ to 0.91 g/cm³. In one particularembodiment, the spunbond layers 146A and 146C can each include acopolymer of polypropylene and polyethylene. The polypropylene can havea refractive index ranging from about 1.44 to about 1.54, such as fromabout 1.46 to about 1.52, such as from about 1.48 to about 1.50, such asabout 1.49, while the polyethylene can have a refractive index rangingfrom about 1.46 to about 1.56, such as from about 1.48 to about 1.54,such as from about 1.50 to about 1.52, such as about 1.51, to impart thematerial 200 with the desired light scattering and light absorbingproperties.

Suitable propylene polymers are commercially available under thedesignations VISTAMAXX™ from ExxonMobil Chemical Co. of Houston, Tex.;FINA™ (e.g., 8573) from Atofina Chemicals of Feluy, Belgium; TAFMER™available from Mitsui Petrochemical Industries; and VERSIFY™ availablefrom Dow Chemical Co. of Midland, Mich. Other examples of suitablepropylene polymers are described in U.S. Pat. No. 6,500,563 to Datta, etal.; U.S. Pat. No. 5,539,056 to Yang, et al.; and U.S. Pat. No.5,596,052 to Resconi, et al., which are incorporated herein in theirentirety by reference thereto for all purposes.

Any of a variety of known techniques may generally be employed to formthe polyolefins. For instance, olefin polymers may be formed using afree radical or a coordination catalyst (e.g., Ziegler-Natta ormetallocene). Metallocene-catalyzed polyolefins are described, forinstance, in U.S. Pat. No. 5,571,619 to McAlpin et at; U.S. Pat. No.5,322,728 to Davis et al.; U.S. Pat. No. 5,472,775 to Obijeski et al.;U.S. Pat. No. 5,272,236 to Lai et al.; and U.S. Pat. No. 6,090,325 toWheat, et al., which are incorporated herein in their entirety byreference thereto for all purposes.

The melt flow index (MI) of the polyolefins may generally vary, but istypically in the range of about 0.1 grams per 10 minutes to about 100grams per 10 minutes, in some embodiments from about 0.5 grams per 10minutes to about 30 grams per 10 minutes, and in some embodiments, about1 to about 10 grams per 10 minutes, determined at 190° C. The melt flowindex is the weight of the polymer (in grams) that may be forced throughan extrusion rheometer orifice (0.0825-inch diameter) when subjected toa force of 2160 grams in 10 minutes at 190° C., and may be determined inaccordance with ASTM Test Method D1238-E.

In addition to a polyolefin, the spunbond layers 146A and 146C can eachinclude a slip additive to enhance the softness of the spunbond layers146A and 146C. The slip additive can also reduce the glare of the firstmaterial 200 in the operating room by reducing the light reflectance ofthe first material and can also render the first material 200 moreopaque than the standard gown material when contacted with fats andlipids during surgery, where the standard gown material turnstransparent upon contact with fats and lipids, which can result in thewearer having some concern that the barrier properties of a standardgown have been compromised.

Variants of fatty acids can be used as slip additives. For example, theslip additive can be erucamide, oleamide, stearamide, behenamide, oleylpalmitamide, stearyl erucamide, ethylene bis-oleamide, N,N′-EthyleneBis(Stearamide) (EBS), or a combination thereof. Further, the slipadditive have a refractive index ranging from about 1.42 to about 1.52,such as from about 1.44 to about 1.50, such as from about 1.46 to about1.48, such as about 1.47, to impart the material 200 with the desiredlight scattering and light absorbing properties by reducing therefractive index. The slip additive can be present in each of the firstspunbond layer 146A and the second spunbond layer 146C in an amountranging from about 0.25 wt. % to about 6 wt. %, such as from about 0.5wt. % to about 5 wt. %, such as from about 1 wt. % to about 4 wt. %based on the total weight of the particular spunbond layer 146A or 146C.In one particular embodiment, the slip additive can be present in anamount of about 2 wt. % based on the total weight of the particularspunbond layer 146A or 146C.

In addition to the polyolefin and slip additive, the spunbond layers146A and 146C can also include one or more pigments to help achieve thedesired gray color of the gown 101. Examples of suitable pigmentsinclude, but are not limited to, titanium dioxide (e.g., SCC 11692concentrated titanium dioxide), zeolites, kaolin, mica, carbon black,calcium oxide, magnesium oxide, aluminum hydroxide, and combinationsthereof. In certain cases, for instance, each of the spunbond layers146A or 146C can include titanium dioxide in an amount ranging fromabout 0.1 wt. % to about 10 wt. %, in some embodiments, from about 0.5wt. % to about 7.5 wt. %, and in some embodiments, from about 1 wt. % toabout 5 wt. % based on the total weight of the particular spunbond layer146A or spunbond layer 146C. The titanium dioxide can have a refractiveindex ranging from about 2.2 to about 3.2, such as from about 2.4 toabout 3, such as from about 2.6 to about 2.8, such as about 2.76, toimpart the material 200 with the desired light scattering and lightabsorbing properties. Further, each of the spunbond layers 146A or 146Ccan also include carbon black in an amount ranging from about 0.1 wt. %to about 10 wt. %, in some embodiments, from about 0.5 wt. % to about7.5 wt. %, and in some embodiments, from about 1 wt. % to about 5 wt. %based on the total weight of the particular spunbond layer 146A orspunbond layer 146C. The carbon black can have a refractive indexranging from about 1.2 to about 2.4, such as from about 1.4 to about2.2, such as from about 1.6 to about 2 to impart the material 200 withthe desired light scattering and light absorbing properties. Inaddition, each of the spunbond layers 146A or 146C can also include ablue pigment in an amount ranging from about 0.1 wt. % to about 10 wt.%, in some embodiments, from about 0.5 wt. % to about 7.5 wt. %, and insome embodiments, from about 1 wt. % to about 5 wt. % based on the totalweight of the individual layer. The combination of the carbon black andblue pigment improves the ability of the spunbond layers 146A or 146C toabsorb light.

The meltblown layer 146B of the spunbond-meltblown-spunbond secondmaterial 300 can also be formed from any of the semi-crystallinepolyolefins discussed above with respect to the first spunbond layer146A and the second spunbond layer 146C of the first material 200. Inone particular embodiment, the meltblown layer 146B can be formed from100% polypropylene.

Regardless of the specific polymer or polymers and additives used toform the SMS laminate 146, the SMS laminate 146 can have a basis weightranging from about 5 gsm to about 50 gsm, such as from about 10 gsm toabout 40 gsm, such as from about 15 gsm to about 30 gsm. In oneparticular embodiment, the SMS laminate 146 can have a basis weight ofabout 22 gsm (about 0.65 osy).

Despite the use of a front panel 102, sleeves 104, and hood 178 (e.g.,all of the hood 178 or at least the first portion 256 of the hood 178 asdescribed above) that are formed from an air impermeable butmoisture-vapor breathable first material 200, the amount of heat thatbecomes trapped can be uncomfortable to the wearer. As such, the presentinventor has discovered that the placement of a highly breathable andair permeable first rear panel 120 and second rear panel 120 formed froma second material 300 in the rear 160 of the gown 101 can facilitate thedissipation of trapped humidity and heat between the gown 101 and thewearer. Further, in some embodiments, a second portion 258 of the hood178 below seam 254 at the rear 160 of the gown 101 can optionally beformed from the second material 300.

In one particular embodiment, the second material 300 can be in the formof a spunbond-meltblown-spunbond (SMS) laminate that has enhanced airbreathability in order to facilitate removal of trapped heated air andmoisture from the gown 101. For instance, the second material 300 allowsfor an air volumetric flow rate ranging from about 20 standard cubicfeet per minute (scfm) to about 80 scfm, such as from about 30 scfm toabout 70 scfm, such as from about 40 scfm to about 60 scfm, asdetermined at 1 atm (14.7 psi) and 20° C. (68° F.). In one particularembodiment, the second material 300 allows for an air volumetric flowrate of about 45 scfm. Because the first rear panel 120, the second rearpanel 122, and lower or second portion 256 of the hood 178 below seam254 at the rear 160 of the gown 101 can be formed from the airbreathable second material 300, the heat and humidity that can build upinside the space between the gown 101 and the wearer's body can escapevia convection and/or by movement of air as the movement of the gownmaterials 200 and 300 changes the volume of space between the gown 101and the wearer's body. Further, the SMS laminate used to form the secondmaterial 300 can have a basis weight ranging from about 20 gsm to about80 gsm, such as from about 25 gsm to about 70 gsm, such as from about 30gsm to about 60 gsm. In one particular embodiment, the second material300 can have a basis weight of about 40 gsm (about 1.2 osy).

The various layers of the second material 300 are discussed in moredetail below.

The first spunbond layer 148 and second spunbond layer 152 of the secondmaterial 300 can be formed from any suitable polymer that providessoftness and air breathability to the second material 300. For instance,the first spunbond layer 148 and the second spunbond layer 152 can beformed from a semi-crystalline polyolefin. Exemplary polyolefins mayinclude, for instance, polyethylene, polypropylene, blends andcopolymers thereof. In one particular embodiment, a polyethylene isemployed that is a copolymer of ethylene and an α-olefin, such as aC₃-C₂₀ α-olefin or C₃-C₁₂ α-olefin. Suitable α-olefins may be linear orbranched (e.g., one or more C₁-C₃ alkyl branches, or an aryl group).Specific examples include 1-butene; 3-methyl-1-butene;3,3-dimethyl-1-butene; 1-pentene; 1-pentene with one or more methyl,ethyl or propyl substituents; 1-hexene with one or more methyl, ethyl orpropyl substituents; 1-heptene with one or more methyl, ethyl or propylsubstituents; 1-octene with one or more methyl, ethyl or propylsubstituents; 1-nonene with one or more methyl, ethyl or propylsubstituents; ethyl, methyl or dimethyl-substituted 1-decene;1-dodecene; and styrene. Particularly desired α-olefin co-monomers are1-butene, 1-hexene and 1-octene. The ethylene content of such copolymersmay be from about 60 mole % to about 99 mole %, in some embodiments fromabout 80 mole % to about 98.5 mole %, and in some embodiments, fromabout 87 mole % to about 97.5 mole %. The α-olefin content may likewiserange from about 1 mole % to about 40 mole %, in some embodiments fromabout 1.5 mole % to about 15 mole %, and in some embodiments, from about2.5 mole % to about 13 mole %.

The density of the polyethylene may vary depending on the type ofpolymer employed, but generally ranges from 0.85 to 0.96 grams per cubiccentimeter (“g/cm³”). Polyethylene “plastomers”, for instance, may havea density in the range of from 0.85 to 0.91 g/cm³. Likewise, “linear lowdensity polyethylene” (“LLDPE”) may have a density in the range of from0.91 to 0.940 g/cm³; “low density polyethylene” (“LDPE”) may have adensity in the range of from 0.910 to 0.940 g/cm³; and “high densitypolyethylene” (“HDPE”) may have density in the range of from 0.940 to0.960 g/cm³. Densities may be measured in accordance with ASTM 1505.Particularly suitable ethylene-based polymers for use in the presentinvention may be available under the designation EXACT™ from ExxonMobilChemical Company of Houston, Tex. Other suitable polyethylene plastomersare available under the designation ENGAGE™ and AFFINITY™ from DowChemical Company of Midland, Mich. Still other suitable ethylenepolymers are available from The Dow Chemical Company under thedesignations DOWLEX™ (LLDPE) and ATTANE™ (ULDPE). Other suitableethylene polymers are described in U.S. Pat. No. 4,937,299 to Ewen etal.; U.S. Pat. No. 5,218,071 to Tsutsui et al.; U.S. Pat. No. 5,272,236to Lai, et al.; and U.S. Pat. No. 5,278,272 to Lai, et al., which areincorporated herein in their entirety by reference thereto for allpurposes.

Of course, the first spunbond layer 148 and the second spunbond layer152 of the second material 300 are by no means limited to ethylenepolymers. For instance, propylene polymers may also be suitable for useas a semi-crystalline polyolefin. Suitable propylene polymers mayinclude, for instance, polypropylene homopolymers, as well as copolymersor terpolymers of propylene with an α-olefin (e.g., C₃-C₂₀) comonomer,such as ethylene, 1-butene, 2-butene, the various pentene isomers,1-hexene, 1-octene, 1-nonene, 1-decene, 1-unidecene, 1-dodecene,4-methyl-1-pentene, 4-methyl-1-hexene, 5-methyl-1-hexene,vinylcyclohexene, styrene, etc. The comonomer content of the propylenepolymer may be about 35 wt. % or less, in some embodiments from about 1wt. % to about 20 wt. %, in some embodiments, from about 2 wt. % toabout 15 wt. %, and in some embodiments from about 3 wt. % to about 10wt. %. The density of the polypropylene (e.g., propylene/α-olefincopolymer) may be 0.95 grams per cubic centimeter (g/cm³) or less, insome embodiments, from 0.85 to 0.92 g/cm³, and in some embodiments, from0.85 g/cm³ to 0.91 g/cm³. In one particular embodiment, the spunbondlayers 148 and 152 can each include a copolymer of polypropylene andpolyethylene. The polypropylene can have a refractive index ranging fromabout 1.44 to about 1.54, such as from about 1.46 to about 1.52, such asfrom about 1.48 to about 1.50, such as about 1.49, while thepolyethylene can have a refractive index ranging from about 1.46 toabout 1.56, such as from about 1.48 to about 1.54, such as from about1.50 to about 1.52, such as about 1.51, to impart the material 300 withthe desired light scattering and light absorbing properties.

Suitable propylene polymers are commercially available under thedesignations VISTAMAXX™ from ExxonMobil Chemical Co. of Houston, Tex.;FINA™ (e.g., 8573) from Atofina Chemicals of Feluy, Belgium; TAFMER™available from Mitsui Petrochemical Industries; and VERSIFY™ availablefrom Dow Chemical Co. of Midland, Mich. Other examples of suitablepropylene polymers are described in U.S. Pat. No. 6,500,563 to Datta, etal.; U.S. Pat. No. 5,539,056 to Yang, et al.; and U.S. Pat. No.5,596,052 to Resconi, et al., which are incorporated herein in theirentirety by reference thereto for all purposes.

Any of a variety of known techniques may generally be employed to formthe polyolefins. For instance, olefin polymers may be formed using afree radical or a coordination catalyst (e.g., Ziegler-Natta ormetallocene). Metallocene-catalyzed polyolefins are described, forinstance, in U.S. Pat. No. 5,571,619 to McAlpin et at; U.S. Pat. No.5,322,728 to Davis et al.; U.S. Pat. No. 5,472,775 to Obiieski et al.;U.S. Pat. No. 5,272,236 to Lai et al.; and U.S. Pat. No. 6,090,325 toWheat, et al., which are incorporated herein in their entirety byreference thereto for all purposes.

The melt flow index (MI) of the polyolefins may generally vary, but istypically in the range of about 0.1 grams per 10 minutes to about 100grams per 10 minutes, in some embodiments from about 0.5 grams per 10minutes to about 30 grams per 10 minutes, and in some embodiments, about1 to about 10 grams per 10 minutes, determined at 190° C. The melt flowindex is the weight of the polymer (in grams) that may be forced throughan extrusion rheometer orifice (0.0825-inch diameter) when subjected toa force of 2160 grams in 10 minutes at 190° C., and may be determined inaccordance with ASTM Test Method D1238-E.

In addition to a polyolefin, the first spunbond layer 148 and the secondspunbond layer 152 can also include a slip additive to enhance thesoftness of the first spunbond layer 148 and the second spunbond layer152. The slip additive can also reduce the coefficient of friction andincrease the hydrohead of the first spunbond layer 148 and the secondspunbond layer 152 of the first rear panel 120 and second rear panel122. Such a reduction in the coefficient of friction lessens the chanceof the gown 101 being cut or damaged due to abrasions and also preventsfluids from seeping through the second material 300. Instead, at leastin part due to the inclusion of the slip additive, fluid that contactsthe outer-facing surface 302 of the gown 101 can remain in droplet formand run vertically to the distal end 156 of the gown 101 and onto thefloor. The slip additive can also reduce the glare of the secondmaterial 300 in the operating room by reducing the light reflectance ofthe first material and can also render the second material 300 moreopaque than the standard gown material when contacted with fats andlipids during surgery, where the standard gown material turnstransparent upon contact with fats and lipids, which can result in thewearer having some concern that the barrier properties of a standardgown have been compromised.

The slip additive can function by migrating to the surface of thepolymer used to form the first spunbond layer 148 and/or the secondspunbond layer 152, where it can provide a coating that reduces thecoefficient of friction of the outer-facing surface 302 and/orbody-facing surface or inner-facing surface 304 of the first material300. Variants of fatty acids can be used as slip additives. For example,the slip additive can be erucamide, oleamide, stearamide, behenamide,oleyl palmitamide, stearyl erucamide, ethylene bis-oleamide,N,N′-Ethylene Bis(Stearamide) (EBS), or a combination thereof. Further,the slip additive can have a refractive index ranging from about 1.42 toabout 1.52, such as from about 1.44 to about 1.50, such as from about1.46 to about 1.48, such as about 1.47, to impart the material 200 withthe desired light scattering and light absorbing properties. The slipadditive can be present in the first spunbond layer 148 and/or thesecond spunbond layer 152 of the second material 300 in an amountranging from about 0.25 wt. % to about 6 wt. %, such as from about 0.5wt. % to about 5 wt. %, such as from about 1 wt. % to about 4 wt. %based on the total weight of the first spunbond layer 148 and/or thesecond spunbond layer 152. In one particular embodiment, the slipadditive can be present in an amount of about 2 wt. % based on the totalweight of the first spunbond layer 148 and/or the second spunbond layer152.

In addition to the polyolefin and slip additive, the spunbond layers 148and 152 can also include one or more pigments to help achieve thedesired gray color of the gown 101. Examples of suitable pigmentsinclude, but are not limited to, titanium dioxide (e.g., SCC 11692concentrated titanium dioxide), zeolites, kaolin, mica, carbon black,calcium oxide, magnesium oxide, aluminum hydroxide, and combinationsthereof. In certain cases, for instance, each of the spunbond layers 148or 152 can include titanium dioxide in an amount ranging from about 0.1wt. % to about 10 wt. %, in some embodiments, from about 0.5 wt. % toabout 7.5 wt. %, and in some embodiments, from about 1 wt. % to about 5wt. % based on the total weight of the particular spunbond layer 148 or152. The titanium dioxide can have a refractive index ranging from about2.2 to about 3.2, such as from about 2.4 to about 3, such as from about2.6 to about 2.8, such as about 2.76, to impart the material 200 withthe desired light scattering and light absorbing properties. Further,each of the spunbond layers 148 or 152 can also include carbon black inan amount ranging from about 0.1 wt. % to about 10 wt. %, in someembodiments, from about 0.5 wt. % to about 7.5 wt. %, and in someembodiments, from about 1 wt. % to about 5 wt. % based on the totalweight of the particular spunbond layer 148 or spunbond layer 152. Thecarbon black can have a refractive index ranging from about 1.2 to about2.4, such as from about 1.4 to about 2.2, such as from about 1.6 toabout 2 to impart the material 300 with the desired light scattering andlight absorbing properties. In addition, each of the spunbond layers 148or 152 can also include a blue pigment in an amount ranging from about0.1 wt. % to about 10 wt. %, in some embodiments, from about 0.5 wt. %to about 7.5 wt. %, and in some embodiments, from about 1 wt. % to about5 wt. % based on the total weight of the individual layer. Thecombination of the carbon black and blue pigment improves the ability ofthe spunbond layers 148 or 152 to absorb light.

The meltblown layer 150 of the spunbond-meltblown-spunbond secondmaterial 300 can also be formed from any of the semi-crystallinepolyolefins discussed above with respect to the first spunbond layer 148and the second spunbond layer 152 of the second material 300. In oneparticular embodiment, the meltblown layer 150 can be formed from 100%polypropylene.

The cuffs 106 and collar 110 (if present) of the disposable surgicalgown 101 of the present invention can be formed from a woven or knitmaterial that is air breathable, soft, and extensible. The collar 110can also be water repellant. In one particular embodiment, the collar110 and the cuffs 104 can be formed from a knit polyester. Because thematerial from which the collar 110 is formed is extensible, the collar110 can stretch and conform to a wearer's particular neck dimensions tolay flat against the wearer's neck and prevent any gapping of the collar110, which could allow bone fragments, blood splatter, and otherbiologic materials to come into contact with the wearer. In any event,the collar 110 can be sewn to the front panel 102, sleeves 104, firstrear panel 120, and second rear panel 122 with a polyester thread.Further, the cuffs 106 can be formed from the same material as thecollar 110, as discussed above. In addition, the cuffs 106 can be sewnto the sleeves 104 with a polyester thread.

In addition to the surgical gown 101 discussed above, it is also to beunderstood that the personal protection and ventilation system 100 withwhich the visor system 180 of the present invention can be used can alsoinclude a helmet 190 with an optional light source 188, an air tube 184,and a belt 206 with an attached fan 182 and power source (e.g., battery216) as described in detail above with reference to FIG. 9.

The present invention has been described both in general and in detailby way of examples. These and other modifications and variations of thepresent invention may be practiced by those of ordinary skill in theart, without departing from the spirit and scope of the presentinvention. In addition, it should be understood that aspects of thevarious embodiments may be interchanged both in whole or in part.Furthermore, those of ordinary skill in the art will appreciate that theforegoing description is by way of example only, and is not intended tolimit the invention so further described in such appended claims.

What is claimed is:
 1. A visor system for a personal protection system,the visor system comprising: a base film; and a first removable filmmechanically bonded to an outer-facing surface of the base film via afirst plurality of mechanical bond points, wherein gaps are presentbetween adjacent mechanical bond points.
 2. The visor system of claim 1,wherein the first removable film includes a tab, wherein the tabfacilitates removal of the first removable film from the base film. 3.The visor system of claim 1, wherein the base film and the firstremovable film are transparent.
 4. The visor system of claim 1, whereinthe base film comprises a polyester or a polycarbonate.
 5. The visorsystem of claim 1, wherein the first removable film comprises apolyester or a polycarbonate.
 6. The visor system of claim 1, whereinthe first plurality of mechanical bond points are ultrasonic bondpoints.
 7. The visor system of claim 1, wherein the gaps permitpenetration of ethylene oxide gas between the base film and the firstremovable film.
 8. The visor system of claim 1, wherein the base filmdefines a perimeter and the first removable film defines a perimeter,wherein the perimeter of the first removable film is containedcompletely within the perimeter of the base film.
 9. The visor system ofclaim 8, wherein the first plurality of mechanical bond points arelocated about the perimeter of the first removable film.
 10. The visorsystem of claim 1, further comprising a second removable film, whereinthe second removable film is mechanically bonded to the first removablefilm via a second plurality of mechanical bond points, wherein gaps arepresent between adjacent mechanical bond points.
 11. The visor system ofclaim 10, wherein the second removable film includes a tab, wherein thetab facilitates removal of the second removable film from the firstremovable film.
 12. The visor system of claim 10, wherein the secondremovable film is transparent.
 13. The visor system of claim 10, whereinthe second removable film comprises a polyester or a polycarbonate. 14.The visor system of claim 10, wherein the second plurality of mechanicalbond points are ultrasonic bond points.
 15. The visor system of claim10, wherein the gaps permit penetration of ethylene oxide gas betweenthe first removable film and the second removable film.
 16. The visorsystem of claim 10, wherein the base film defines a perimeter and thesecond removable film defines a perimeter, wherein the perimeter of thesecond removable film is contained completely within the perimeter ofthe base film.
 17. The visor system of claim 16, wherein the secondplurality of mechanical bond points are located about the perimeter ofthe second removable film.
 18. The visor system of claim 1, wherein thevisor system is ethylene oxide gas sterilized.
 19. A surgical hoodcomprising the visor system of claim 1, wherein the surgical hood andthe visor system are ethylene oxide gas sterilized.
 20. A surgical gowncomprising an integrated surgical hood and the visor system of claim 1,wherein the surgical gown, the integrated surgical hood, and the visorsystem are ethylene oxide gas sterilized.
 21. A personal protectionsystem including a surgical gown and a separate surgical hood comprisingthe visor system of claim 1, wherein the personal protection system isethylene gas sterilized in a single package.